Skip to main content

Full text of "Science of home and community, a text-book in general science"

See other formats


B 


I 

; 


•;       -"lUM^ 


m 


;  iVIUIMJ 

raftc  >n 

--.'l~»  S,-.    -r  -'."        ,    -.      -..  .. 

1 1        fc,.: 


GIFT   OF 


SCIENCE   OF   HOME   AND   COMMUNITY 


THE  MACMILLAN  COMPANY 

NEW  YORK    •    BOSTON  •    CHICAGO  •    DALLAS 
ATLANTA  •   SAN  FRANCISCO 

MACMILLAN  &  CO.,  LIMITED 

LONDON  •    BOMBAY  •    CALCUTTA 
MELBOURNE 

THE  MACMILLAN  CO.  OF  CANADA,  LTD. 

TORONTO 


SCIENCE   OF   HOME  AND 
COMMUNITY 

A    TEXT-BOOK  IN  GENERAL   SCIENCE 


BY 
GILBERT   H.   TRAFTON 

INSTRUCTOR   IN   SCIENCE   AT  THE   STATE 
NORMAL   SCHOOL,    MANKATO,    MINN. 


gotk 

THE   MACMILLAN   COMPANY 
1920 

All  rights  reserved 


COPYRIGHT,  1919, 
BY  THE  MACMILLAN   COMPANY. 


Set  up  ^nfljclectiotyped.     Published  October,  1919. 


PREFACE 

EDUCATION  for  the  present  life  of  the  child  should  be  the 
chief  purpose  of  our  schools.  This  book  seeks  to  carry  out 
this  principle  so  far  as  science  is  concerned.  We  are  living 
in  the  midst  of  a  great  scientific  age.  Applications  of  science 
more  and  more  dominate  our  life,  and  they  will  continue 
to  do  so  in  ever-increasing  degree.  Any  sane  system  of 
education  must  see  to  it  that  boys  and  girls  living  in  the 
midst  of  these  applications,  which  form  such  an  important 
part  of  their  everyday  life,  are  educated  in  terms  of  this 
environment,  in  order  that  they  may  better  appreciate  it 
and  adapt  themselves  to  it.  This  book  is  an  attempt  to 
make  clear  to  boys  and  girls  answers  to  some  of  the  ques- 
tions naturally  arising  in  their  minds  concerning  the  com- 
mon applications  of  science. 

The  book  is  not  written  as  an  introduction  to,  or  prepara- 
tion for,  any  later  science  work.  It  is  written  to  meet  the 
present  needs  and  interests  of  boys  and  girls  just  entering  the 
adolescent  period.  We  do  not  know  the  future  of  the  child, 
but  we  do  know  his  present.  The  satisfaction  of  these 
present  needs  is  the  best  possible  and  the  only  sound  founda- 
tion for  any  further  work  in  science  that  he  may  do  in  later 
years. 

If  a  course  in  General  Science  is  to  be  worthy  of  an  es- 
tablished place  in  the  school  curriculum,  it  must  fulfill 
two  requirements :  first  and  foremost,  it  must  appeal  to  the 
pupils  ;  and  second,  it  must  be  well  organized  around  centers 
of  children's  interests.  • 

46QOQ? 


NOTE  TO  TEACHERS 

THE  practical  work  outlined  in  this  book  has  been  divided 
into  four  kinds :  laboratory  exercises,  demonstrations,  field 
exercises,  and  projects.  The  demonstrations  are  to  be 
done  before  the  class  either  by  the  instructor  or  by  some 
pupil.  It  is  intended  that  the  laboratory  exercises  shall 
be  performed  by  each  pupil.  The  extent  to  which  each 
pupil  can  do  the  laboratory  exercises  will  depend  on  the 
equipment  and  the  facilities  available  for  individual  work. 
If  equipment  is  lacking,  the  laboratory  exercises  may  be 
performed  as  demonstrations.  The  field  exercises  are  to 
be  done  by  the  instructor  and  class  outside  of  the  school- 
room. In  the  projects  something  is  provided  for  each  pupil 
to  do  individually  outside  of  the  laboratory.  These  proj- 
ects have  been  divided  into  three  groups :  for  the  home, 
for  the  school,  and  for  the  community.  They  provide  a 
vital  kind  of  work  because  they  connect  the  school  work  with 
actual  life  and  provide  opportunity  for  the  pupil  to  do  some- 
thing on  his  own  responsibility.  It  is  suggested  that  a  cer- 
tain number  of  home  projects  be  required  of  each  pupil, 
who  may  be  allowed  to  choose  the  ones  he  wishes  to  carry 
on.  The  pupils  should  be  expected  to  present  definite  written 
reports  of  the  projects  and  should  be  given  school  credit 
for  the  work  done.  A  sufficient  variety  of  projects  has  been 
given  so  that  each  pupil  can  find  some  suited  to  his  cir- 
cumstances. 

The  author  believes  that  the  pupils  should  make  some 
written  records  of  all  the  practical  exercises.  These  records, 
kept  in  a  notebook,  should  be  brief  and  simple  in  form.  It 
is  suggested  that  each  record  may  contain,  first,  a  statement 


X  NOTE    TO    TEACHERS 

of  the  purpose  of  the  exercise;  second,  a  brief  description 
of  what  was  done ;  and  third,  a  statement  of  the  things 
learned  or  the  conclusions  drawn  from  the  exercise. 

Questions  at  the  beginning  of  each  chapter  are  given  as 
problems  to  guide  the  pupils  in  their  study.  These,  to- 
gether with  the  questions  at  the  end  of  the  chapter,  are 
suggested  as  a  basis  for  the  class  discussions.  It  is  believed 
that  a  few  leading  questions  of  this  type  will  stimulate  the 
pupils  to  independent  thought  and  to  organization  of  their 
knowledge. 

In  order  to  adapt  the  work  to  the  individual  interests  and 
capabilities  of  the  pupils,  it  seems  desirable  that  students 
make  reports  to  the  class  on  some  subjects  of  which  they 
have  made  special  study.  As  an  aid  in  this  line  of  work  a 
few  references  are  given  at  the  close  of  each  chapter. 
.  The  stress  to  be  laid  on  the  various  chapters  depends  on 
the  environment  of  the  pupils,  whether  it  is  urban  or  rural. 
In  accordance  with  this  environment  some  chapters  may  be 
passed  over  lightly,  while  others  should  receive  special 
attention. 


TABLE  OF   CONTENTS 

PART   I.     SCIENCE   OF  THE   HOME 
SECTION  A.     HYGIENE  OF  THE  HOME 

CHAPTER 

I.  HEATING  THE  HOME 3 

II.  VENTILATING  THE  HOME 17 

III.  LIGHTING  THE  HOME  . 33 

IV.  THE  HOME  WATER  SUPPLY 45 

V.  THE  HYGIENE  OF  THE  DINING  ROOM        ...  58 

VI.  SCIENCE  OF  THE  KITCHEN 98 

SECTION  B.     PLEASURE   IN   THE   HOME 

VII.  MUSICAL  INSTRUMENTS 118 

VIII.  TAKING  PICTURES        .        .        .        .        .        .        .  126 

IX.  HOUSE  PLANTS 138 

SECTION  C.    ELECTRICITY  IN  THE  HOME 
X.  APPLICATIONS  OF  ELECTRICITY    .        .        .        .        .148 

SECTION   D.    ySE  OF  THE  HOME   GROUNDS 

XI.  THE  ORNAMENTATION  OF  THE  HOME  GROUNDS          .  161 

XII.  THE  VEGETABLE  GARDEN 180 

XIII.  THE  FRUIT  GARDEN 203 

XIV.  POULTRY  KEEPING  AND  BEE  KEEPING       .        .        .  214 
XV.  ATTRACTING  BIRDS  AROUND  THE  HOME  226 


xii  TABLE    OF    CONTENTS 

PART   II.     SCIENCE   OF  THE   COMMUNITY 

SECTION   A.     MEANS  OF  TRAVEL 

Group  A .     Travel  on  Land 
XVI.   THE  LOCOMOTIVE         .        .        .        .        .        .        .243 

XVII.  THE  ELECTRIC  TROLLEY 257 

XVIII.  THE  AUTOMOBILE 266 

Group  B.     Travel  by  Water 
XIX.  THE  STEAMBOAT  AND  SUBMARINE       ....    284 

Group  C.     Travel  by  Air 
XX.  AIRSHIPS  AND  AIRPLANES 300 

SECTION   B.     MEANS  OF  COMMUNICATION 

XXI.  THE  TELEGRAPH 318 

XXII.   THE  TELEPHONE 333 

SECTION   C.     THE   HEALTH  OF  THE   COMMUNITY 

XXIII.  THE  PUBLIC  WATER,  MILK,  AND  FOOD  SUPPLY         .    347 

XXIV.  CONTAGIOUS  DISEASES        .        .        .        .        .        .365 

XXV.  INSECTS  AND  DISEASE 394 

XXVI.   HEALTH  OFFICERS 417 

XXVII.   SCHOOL  HYGIENE 426 

SECTION   D.     COMMUNITY  ENTERTAINMENT 
XXVIII.    THE  MOVING  PICTURES       .        .  .        .        .    444 

SECTION  E.     CONSERVATION  OF  COMMUNITY  RESOURCES 

XXIX.   PROTECTION  OF  BIRDS 459 

XXX.  CONSERVATION  OF  FORESTS 478 


TABLE    OF    CONTENTS  xiii 

SECTION   F.     PROTECTION   FROM   WEATHER 
XXXI.  THE  UNITED  STATES  WEATHER  BUREAU    .        .        .503 

SECTION    G.     RELATION    OF    EARTH    TO     THE     OTHER 
HEAVENLY   BODIES 

XXXII.  THE  EARTH  AS  A  PART  OF  THE  SOLAR  SYSTEM  .     515 

SECTION    H.     AN    ENEMY    OF    HOME   AND    COMMUNITY 

XXXIII.  ALCOHOLIC  DRINKS 536 

APPENDIX 

TABLE  OF  RELATIVE  HUMIDITY 55  c 

LIST  OF  APPARATUS 556 

TABLE  OF  INVENTIONS 557 


PART  I 
SCIENCE  OF  THE  HOME 


SCIENCE  OF   HOME  AND 
COMMUNITY 

SECTION  A 
HYGIENE  OF  THE  HOME 

CHAPTER   I 
HEATING   THE   HOME 

1 .  In  what  ways  are  our  present  modes  of  heat- 
ing better  than  those  used  in  early  times  ? 

2.  What  advantages  has  each  of  the  following 
methods  of  heating  the  home :  hot  air,  hot  water, 
and  steam  ? 

Early  methods  of  heating.  People  have  become  so  accus- 
tomed to  the  methods  now  used  to  heat  their  homes  that  they 
do  not  often  stop  to  think  that  these  same  methods  have  not 
always  been  used  and  that  a  hundred  years  ago  people  did 
not  have  the  same  conveniences  for  heating  that  we  now 
enjoy.  Our  present  methods  of  heating,  as  well  as  numer- 
ous other  conveniences,  have  come  to  us  only  gradually 
after  many  changes  and  improvements  running  back  hun- 
dreds of  years.  Let  us  consider  briefly  the  changes  in  meth- 
ods of  heating  that  have  taken  place  from  the  very  earliest 
times  up  to  the  present  day. 

The  first  method  of  heating  used  by  primitive  man  many 
centuries  ago  was  to  build  a  fire  on  the  earth  floor  of  his 
crude  hut  and  allow  the  smoke  to  escape  through  a  hole  in 

3 


4  \/ SCIENCE  OF  HOME  AND   COMMUNITY 

the  tcip  of  the  hut.  ;  As  there  was  no  chimney,  the  smoke 
was  often  blown  down  the  opening  and  filled  all  parts  of 
the  hut.  This  method  was  probably  used  for  thousands 
of  years. 

The  primitive  fireplace.  When  the  first  chimney  was 
built  the  fire  was  moved  to  one  side  of  the  room,  a  hole 
was  cut  in  the  wall  just  over  it,  and  a  hood  was  made  that 
projected  out  over  the  fire  to  collect  the  smoke.  A  little  later 
this  was  improved  by  making  a  recess  in  the  wall  for  the  fire- 
place and  building  a  separate  chimney  to  carry  off  the  smoke. 
By  the  end  of  the  fifteenth  century  these  fireplaces  were 
in  common  use  throughout  the  civilized  world.  For  two 
hundred  years  after  the  settlement  of  this  country  by  white 
people,  they  depended  entirely  upon  the  open  fireplace  to 
warm  their  homes  during  the  cold  winters.  In  the  early 
days  the  churches  were  not  heated  at  all. 

Primitive  stoves  and  furnaces.  The  next  improvement 
in  heating  was  the  invention  of  the  stove.  At  first  it  con- 
sisted of  an  iron  box  provided  with  openings  at  the  top  for 
the  escape  of  the  smoke,  which  passed  out  into  the  room. 
Charcoal  was  often  burned  in  it,  as  that  did  not  give  off  much 
smoke.  The  next  step  was  to  connect  a  pipe  with  this  box  to 
carry  the  smoke  outdoors.  The  first  stove  of  this  type 
was  made  about  two  hundred  years  ago. 

Stoves  were  first  used  in  this  country  about  fifty  years 
before  the  Revolutionary  War.  About  thirty-five  years  before 
this  war  (in  1742)  Benjamin  Franklin  invented  the  stove 
that  was  named  after  him.  The  Franklin  stove  was  a  box 
with  metal  sides  and  entirely  open  in  front.  It  was  set 
in  the  fireplace  and  connected  with  the  flue  of  the  chimney. 
This  was  a  great  improvement  over  the  fireplace.  Other 
improvements  were  continually  made  until  the  modern 
stove  that  we  use  to-day  was  developed. 

The  next  great  advance  made  in  heating  was  the  plan 
of  placing  a  single  large  stove,  called  a  furnace,  in  the 


HEATING  THE  HOME  5 

cellar  and  heating  the  entire  house  by  means  of  this. 
The  first  furnaces  were  used  only  about  one  hundred  yeaf  s 
ago. 

Modern  heating.  The  modern  fireplace.  Fireplaces  are 
still  frequently  built  into  houses,  both  because  they  are 
ornamental  and  because  the  open  fire  is  attractive.  Dur- 
ing the  late  spring  and  early  fall,  when  it  is  not  cold  enough 
to  start  the  furnace,  these  fireplaces  serve  a  useful  purpose 
in  taking  off  the  chill  during  the  evening ;  but  as  a  means 
of  heating,  the  fireplace  is  ineffective  and  expensive.  It  is 
ineffective  because  it  raises  the  air  near  it  to  an  extremely 
high  temperature,  while  the  air  in  distant  parts  of  the  room 
is  heated  only  slightly ;  it  is  expensive  because  so  much 
heat  is  wasted  in  the  heated  air  that  passes  up  the  chimney, 
and  a  large  amount  of  fuel  is  required  to  keep  the  fire  going. 
It  is  not  adapted  to  cold  climates. 

The  modern  stove.  The  stove  is  a  great  improvement  on 
the  fireplace  in  that  it  warms  the  room  more  satisfactorily 
and  requires  less  fuel.  The  stove  heats  the  room  by  a 
process  called  convection.  The  heated  air  over  the  stove 
rises  and  circulates  to  other  parts  of  the  room,  while  the 
colder  air  rushes  in  over  the  stove  and  is  heated.  By  this 
means  a  larger  part  of  the  air  of  a  room  is  heated  than 
would  be  possible  by  a  fireplace.  While  in  the  fireplace  the 
fuel  is  burned  in  the  open,  frequently  filling  the  room  with 
smoke,  in  the  stove  the  fuel  is  burned  in  a  closed  firebox 
with  a  special  pipe  for  carrying  off  the  smoke.  The  stove 
has  the  further  advantage  that  it  is  provided  with  dampers 
by*  means  of  which  the  fire  may  be  controlled.  When 
coal  is  first  put  into  the  stove,  the  back  damper  should 
be  opened  to  allow  the  escape  of  poisonous  gases  that  form, 
as  otherwise  these  may  be  forced  back  into  the  room.  Cook 
stoves  are  so  built  that  the  heated  gases  may  be  forced  to 
pass  around  the  oven,  thus  heating  it  before  passing  up 
through  the  pipe  and  chimney. 


SCIENCE  OF  HOME  AND   COMMUNITY 


The  hot-air  furnace.  One  disadvantage  of  heating  by 
stoves  Hes  in  the  fact  that  several  stoves  are  needed  to  warm 
the  whole  house.  Hence,  systems  are  now  very  widely 
used  in  which  the  whole  house  is  heated  from  one  furnace 
located  in  the  cellar,  the  heat  being  carried  to  the  various 

rooms  by  means  of 
either  hot  air,  or  hot 
water,  or  steam.  The 
hot-air  furnace  is  a 
large  stove  sur- 
rounded with  a  metal 
jacket,  with'  space  be- 
tween to  allow  air 
to  circulate.  Air  is 
brought  into  this  in- 
closed space  by  a  duct 
leading  from  out- 
doors, from  the  cellar, 
or  from  the  rooms 
above ;  and  as  it  passes 
over  and  around  the 
furnace  it  becomes 
heated.  The  furnaces 
are  constructed  so  as 
to  give  a  large  heating 
surface.  From  the 
top  of  the  air  jacket, 
pipes  lead  to  the  sev- 
eral rooms  to  conduct  the  hot  air  through  registers  placed 
either  in  the  floor  or  on  the  walls  near  the  floor.  Fre- 
quently these  pipes  are  covered  with  asbestos  to  reduce  the 
loss  of  heat.  Each  pipe  usually  has  a  damper  near  the 
furnace  and  a  register  in  the  room  that  may  be  opened  or 
closed,  by  means  of  which  the  hot  air  supply  may  be  shut 
off  from  one  part  of  the  house  and  sent  to  other  rooms. 


*    I 


FIG.  i.  —  Hot-air  system. 


HEATING   THE   HOME.  7 

The  circulation  of  air  through  these  pipes  is  maintained 
through  the  effect  of  heat  on  gases.  When  air  is  heated  it 
expands  and  so  becomes  lighter,  while  the  air  coming  in 
from  outdoors  is  colder  and  heavier.  When  two  gases  of 
unequal  weight  are  brought  into  contact,  the  tendency  is 
for  the  heavier  body  to  sink  to  the  bottom  and  push  the 
lighter  gas  up.  So  here  the  cold  air  rushes  in  under  the  warm 
air,  which  is  thus  forced  upwards. 

DEMONSTRATION  i 

Purpose.  To  study  the  principles  applied  in  the  hot-air 
furnace. 

Apparatus.  Flask,  rubber  stopper  with  a  single  hole  to  fit, 
glass  tubing  about  a  foot  long,  alcohol  lamp  or  Bunsen  burner, 
tumbler,  chimney,  touch  paper  or  piece  of  cloth,  candle. 

Directions,  i.  Push  the  glass  tubing  through  the  hole  in  the 
stopper  and  insert  the  stopper  in  the  flask.  Fill  the  tumbler 
with  water  and  place  the  end  of  the  tube  in  it.  Heat  the  flask 
gently  and  notice  what  happens  at  the  end  of  the  tube.  What 
is  the  explanation  ?  Remove  the  lamp  but  allow  the  end  of  the 
tube  to  remain  in  the  water.  Explain  what  happens. 

2.  Light  a  candle.     On  the  table  on  each  side  of  the  candle 
put  a  match ;  on  the  matches  place  a  lamp  chimney.     Light  a 
joss  stick  or  piece  of  cloth  and  hold  at  the  lower  end  of  the 
chimney  near  the  matches.     What  do  you  notice  inside  of  the 
chimney  ?     What  does  this  show  ? 

3.  How  are  the  principles  illustrated  by  these  two  experiments 
applied  in  the  hot-air  furnace  ? 

The  hot-water  system.  In  the  hot-water  system  the  water 
is  heated  in  the  basement  by  the  furnace  and  is  then  con- 
ducted through  pipes  to  radiators  situated  in  the  various 
rooms.  (See  figure  2.)  In  the  attic  is  placed  a  tank  con- 
nected with  this  set  of  pipes.  The  hot  water  passes  to  this 
tank  and  to  the  radiators,  and  then  back  to  the  furnace, 
where  it  is  reheated. 


8 


SCIENCE  OF  HOME  AND   COMMUNITY 


The  explanation  of  the  circulation  of  the  water  is  similar 
to  that  of  the  circulation  of  the  air  in  the  hot-air  system. 
When  water  is  heated,  it  expands  and  becomes  lighter  and 
is  pushed  up  by  the  cold  water,  which  descends  to  the  furnace 
where  it  is  reheated,  thus  keeping  a  constant  circulation  of 

water  through  the  pipes. 
This  is  called  the  direct 
method  of  heating. 

In  another  method  of 
heating,  the  coils  contain- 
ing the  hot  water  are 
placed  in  the  basement, 
and  fresh  air  from  outside 
is  drawn  in  and  heated  and 
then  distributed  to  the 
various  rooms  by  means 
of  pipes  and  registers,  as 
in  the  hot-air  system.  This 
is  called  the  indirect  method 
of  heating.  (See  figure  5.) 
This  system  has  an  ad- 
vantage over  the  direct 
FIG.  2.  -  Hot-water  system.  method  in  that  it  provides 

better  ventilation. 

In  still  another  system  the  radiators  are  placed  in  each 
room  as  in  the  direct  method,  and  an  opening  from  outside 
near  the  radiators  brings  in  fresh  air,  which  is  heated  by 
passing  over  the  radiators.  This  is  called  the  direct-indirect 
method.  (See  figure  6.) 

DEMONSTRATION  2 

Purpose.   To  study  the  principles  applied  in  hot-water  heating. 

Apparatus.  Flask,  stopper  and  tube  used  in  previous  ex- 
periment, two  flasks  with  two-hole  rubber  stoppers,  two  pieces 
of  glass  tubing  about  ten  inches  long. 


HEATING  THE  HOME 


9 


Directions,  i.  Fill  the  flask  with  water  and  insert  the 
stopper  so  that  water  stands  in  the  tube  about  an  inch  from  the 
stopper.  Tie  a  colored  string  around  the  tube  at  the  surface 
of  the  water.  Heat  the  flask  and  watch  the  liquid  in  the  tube. 
Remove  the  lamp  and  allow  the  water  to  cool.  What  happens 
to  the  water  in  the  tube  in  each  case  ?  What  does  this  show  ? 

2.  Secure  two  flasks,   one  a  little  smaller  than  the  other. 
Break  a  hole  in  the  bottom  of  the  smaller  one.     Fill  the  larger 
flask  with  water  and  insert  a  rubber  stopper  with  two  holes. 
Through  these  holes  push  two  pieces  of  glass  tubing  about  ten 
inches  long.     Push  in  one  tube  until  it  just  passes  through  the 
stopper.     Push  in  the  other  tube  about  halfway  to  the  bottom 
of  the  flask.     Invert  the  other  flask,  insert  a  rubber  stopper 
with  two  holes  and  push  in  the  ends  of  the  glass  tubings.     Add 
water  until  the  upper  ends  of  the  tubing  are  covered.     Add  a 
few  drops  of  red  ink.     Heat 

the  lower  flask  and  notice 
the  circulation  of  the  water. 

3.  How  are  the  principles 
illustrated  in  these  two  ex- 
periments   applied    in    the 
hot-water  heating  ? 


Steam  heating.  The 
method  of  heating  by 
steam  is  similar  to  the  hot- 
water  method  except  that 
steam  instead  of  hot  water 
circulates.  There  is  a 
similar  system  of  radiators 
connected  by  pipes  with 
the  furnace.  At  the  fur- 
nace the  boilers  are  so  ar- 
ranged that  the  water  is 
changed  into  steam,  which 


FIG.  3.  —  A  steam-heating  system. 


then    circulates    through    the   pipes.      The  same   indirect 
method,  as  explained  under  the  hot-water  system,  and  like- 


10  SCIENCE   OF   HOME  AND    COMMUNITY 

wise  the  direct-indirect  method  explained  above  may  be 
used. 

The  source  of  the  heat  in  the  steam  is  due  not  merely  to 
the  fact  that  the  steam  is  hot,  but  largely  to  the  fact  that 
when  steam  condenses  it  gives  off  a  large  amount  of  heat. 
When  water  is  boiled,  it  takes  a  large  amount  of  heat  to 
change  it  into  steam.  When  we  wish  to  measure  the  amount 
of  heat,  we  use  a  standard  called  the  calorie,  as  we  use  the 
pound  to  measure  weight.  A  calorie  represents  the  amount 
of  heat  necessary  to  raise  the  temperature  of  one  gram  of 
water  one  degree  Centigrade.  It  requires  over  five  hundred 
calories  to  change  one  gram  of  water  into  steam,  that  is, 
over  five  times  the  amount  of  heat  needed  to  heat  water 
from  the  freezing  point  to  the  boiling  point.  This  heat  is 
stored  up  in  the  steam,,  and  when  the  steam  condenses, 
the  heat  is  given  out  to  surrounding  objects.  It  is  the 
condensing  of  steam  that  furnishes  most  of  the  heat.  Pro- 
vision is  made  for  pipes  to  take  the  water  thus  formed 
back  to  the  furnace. 

DEMONSTRATION  3 

Purpose.     To  learn  the  source  of  heat  in  the  steam-heating 

system. 

Apparatus.  Flask,  rubber  stopper  with  one  hole,  piece  of 
glass  tubing  about  eighteen  inches  long,  beaker,  ringstand, 
thermometer. 

Directions.  Bend  the  tubing  twice  at  right  angles  so  that  the 
two  arms  are  parallel  and  point  in  the  same  direction.  One  of 
these  arms  should  be  about  three  inches  long,  and  the  other  arm 
about  eight  inches  long.  Fill  the  flask  a  third  full  of  water  and 
insert  a  rubber  stopper  with  one  hole.  Push  the  short  arm  of 
the  tubing  through  the  hole  in  the  stopper.  Support  the  flask 
on  a  ringstand.  Fill  a  beaker  with  cold  water  and  place  it  so 
that  the  long  arm  of  the  tubing  dips  below  the  surface  of  the 
water  in  the  beaker.  Take  the  temperature  of  the  water.  Heat 
v,ne  water  in  the  flask.  After  it  has  boiled  five  minutes,  take 


HEATING  THE  HOME  II 

the  temperature  again  of  the  water  in  the  beaker.  How  much 
has  the  temperature  changed?  What  was  the  source  of  this 
heat? 

The  hot-water  system  has  one  great  advantage  over  the 
steam  system  in  that  the  water  can  be  heated  to  any  desired 
temperature  and  thus  can  be  easily  regulated  in  the  mild 
weather;  while  in  the  steam  system  the  water  must  be 
heated  to  the  boiling  point  before  any  results  are  obtained, 
and  in  mild  weather  it  is  difficult  to  keep  the  temperature 
sufficiently  low. 

HOME  PROJECT  i 

Purpose.  To  make  a  study  of  the  heating  system  used  in  your 
home. 

Directions,  i.  If  your  house  is  heated  by  hot  air,  steam,  or 
hot  water,  make  a  careful  study  of  the  different  parts  of  the 
system.  Begin  with  the  furnace  and  notice  where  the  various 
pipes  lead,  and  trace  the  circulation  of  air,  water,  or  steam 
through  the  house  and  back  to  the  furnace.  Make  a  drawing 
of  a  section  of  the  house  from  the  garret  to  the  cellar,  showing 
the  different  parts  of  the  system  in  their  proper  position. 

2.  Make  a  study  of  a  cook  stove  when  there  is  no  fire  in  it,  so 
that  it  can  be  taken  apart.  Make  a  drawing  of  a  cross  section  of 
the  stove.  Label  in  the  drawing  the  following  parts:  ash  pan, 
grate,  draft  damper,  oven  damper,  oven  clean  out.  By  means  of 
black  arrows  show  the  path  of  the  smoke  and  products  of  combus- 
tion around  the  oven  and  up  the  flue  when  the  oven  damper  is  up. 
By  means  of  red  arrows  show  the  path  when  the  damper  is  down. 
Notice  how  the  stove  may  be  cleaned  out. 

Heating  by  electricity.  The  latest  improvement  in 
heating  is  the  use  of  electricity.  This  method  is  very  con- 
venient and  does  away  with  the  smoke  and  dirt  of  stoves 
and  furnaces.  At  present  it  is  just  in  its  beginnings  and  is 
now  too  expensive  for  common  use.  In  the  future,  improve- 
ments will  doubtless  be  made  and  electricity  will  be  sold  at 


12  SCIENCE  OF  HOME  AND   COMMUNITY 

a  lower  price,  hence  it  is  quite  possible  that  a  hundred  years 
from  now,  electricity  may  be  the  common  method  of  heat- 
ing. As  the  stoves  and  furnaces  of  to-day  have  taken  the 
place  of  the  fireplaces  formerly  in  common  use,  so  in  the 
future,  electric  radiators  may  take  the  place  of  stoves  and 
furnaces. 

The  chemistry  of  burning.  The  source  of  heat  in  any 
of  these  systems,  excepting  electricity,  is  the  burning  of  the 
fuel.  In  coal  the  chief  element  is  carbon.  In  wood,  too,  this 
is  found,  together  with  other  elements  including  a  gas  called 
hydrogen,which  also  burns.  The  burning  of  coal  consists  in 
the  union  of  the  oxygen  of  the  air  with  the  carbon,  forming  an 
invisible  gas  called  carbon  dioxid,  and  consists  to  a  lesser  ex- 
tent in  a  union  with  hydrogen,  forming  water.  In  breathing 
we  give  off  the  same  gas,  which  is  formed  in  our  bodies  in  a 
similar  way,  but  not  so  rapidly,  by  the  union  of  oxygen  and 
carbon.  This  process  of  uniting  with  oxygen  takes  place  in 
all  ordinary  types  of  burning,  as  in  the  candle  and  the  kero- 
sene lamp. 

Fuels  are  of  three  kinds :  solid,  such  as  coal  and  wood ; 
liquid,  such  as  kerosene ;  and  gaseous,  such  as  illuminating 
gas.  Coal  and  wood  are  the  fuels  most  commonly  used  for 
heating  purposes. 

Coals  are  divided  into  two  classes,  the  hard  and  the  soft. 
The  hard  coal  contains  a  larger  per  cent  of  carbon,  and  the 
soft  coal  a  larger  per  cent  of  volatile  substances  that  are 
driven  off  when  the  coal  is  heated.  These  substances  are 
not  completely  burned,  and  as  a  result  a  large  amount  of 
smoke  is  formed.  In  order  that  the  fire  may  continue  to 
burn,  the  various  products  formed  must  be  carried  off  through 
the  chimney ;  and  a  new  supply  of  oxygen  must  be  furnished. 
The  fire  is  controlled  by  means  of  dampers  which  regulate 
the  amount  of  air  that  enters.  The  important  part  of  the 
air  for  the  purpose  of  burning  is  oxygen.  This  constitutes 
about  one  fifth  of  the  air.  Experiments  with  pure  oxygen 


HEATING  THE  HOME  13 

show  that  substances  burn  much  more  vigorously  in  it  than 
in  air. 

Before  a  substance  will  burn,  it  must  be  heated  to  a  cer- 
tain temperature  called  the  kindling  temperature.  In 
kindling  fires,  substances  are  first  used  with  a  low  kindling 
temperature,  such  as  paper,  then  this  sets  fire  to  a  substance 
with  a  higher  kindling  temperature,  like  wood,  and  finally 
the  wood  in  burning  heats  up  a  substance  like  hard  coal  with 
a  still  higher  kindling  temperature,  till  it,  too,  burns. 

DEMONSTRATION  4 

Purpose.     To  prepare  oxygen  and  study  its  properties. 

Apparatus.  Test  tube,  glass  tubing  about  eighteen  inches 
long,  pneumatic  trough,  four  wide-mouthed  glass  bottles,  po- 
tassium chlorate,  manganese  dioxid,  oxone,  sulfur,  iron  picture 
wire,  deflagrating  spoon. 

Directions.  A.  Preparation  of  oxygen.  I.  Fill  the  test 
tube  half  full  of  a  mixture  of  equal  parts  of  potassium  chlorate 
and  manganese  dioxid.  Insert  a  stopper  with  a  hole.  Bend 
the  glass  tube  about  three  inches  from  one  end  to  make  an  acute 
angle,  and  at  the  same  distance  from  the  other  end  bend  it  to 
make  an  obtuse  angle.  Insert  the  end  with  the  acute  angle  in 
the  hole  of  the  stopper,  and  put  this  in  the  test  tube.  Support 
the  tube  on  the  ring  of  a  ringstand.  Place  the  other  end  of 
the  tube  under  the  shelf  of  the  pneumatic  trough.  Fill  the 
trough  with  water  to  cover  the  shelf.  Fill  four  wide-mouthed 
bottles  with  water  and  invert  on  the  shelf. 

2.  Heat  the  test  tube  gently,  allowing  the  first  bubbles  to  es- 
cape.    Then  place  one  bottle  with  the  mouth  over  the  opening 
in  the  shelf  so  as  to  collect  the  gas.     When  the  water  has  all 
been  forced  out,  remove  the  bottle  and  put  another  in  its  place. 
In  this  way  fill  four  bottles. 

3.  In  place  of  potassium  chlorate  and  manganese  dioxid 
oxone  may  be  used.     The  advantage  of  using  this  is  that  it  is 
not  necessary  to  heat  the  substance.     It  may  be  placed  in  a 
bottle  and  when  water  is  added,  oxygen  is  given  off  at  once. 


14  SCIENCE  OF  HOME  AND   COMMUNITY 

B.  Properties  of  oxygen.  I.  Invert  one  of  the  bottles  and 
put  in  it  a  burning  splint.  How  does  the  action  compare  with 
that  in  the  air?  Pour  in  a  little  limewater,  shake  the  bottle. 
The  white  precipitate  shows  the  presence  of  carbon  dioxid. 

2.  Fasten  a  wire  to  a  candle,  light  the  candle  and  plunge  it 
into  a  second  bottle.     Note  results. 

3.  Put  some  powdered  sulfur  in  a  deflagrating  spoon.     Ignite 
it  in  a  flame  and  then  lower  it  in  a  third  bottle.     Note  the 
difference  between  burning  in  air  and  in  oxygen. 

4.  Wrap  a  small  piece  of  cloth  around  the  end  of  an  iron 
picture  wire.     Roll  this  in  powdered  sulfur  and  hold  it  in  the 
flame.     When  it  has  started  burning,  lower  it  into  a  fourth 
bottle  of  oxygen. 

5.  What  conclusions  do  you  draw  from  these  experiments 
regarding  the  properties  of  oxygen  and  the  difference  between 
burning  in  air  and  in  pure  oxygen  ? 

LABORATORY  EXERCISE  i 

Purpose.  To  study  the  burning  of  wood,  soft  coal,  and  hard 
coal. 

Apparatus.  Ringstand,  wire  gauze,  gas  burner  or  alcohol 
lamp,  small  piece  of  wood,  soft  coal,  and  hard  coal. 

Directions.  I.  Place  a  small  piece  of  wood  on  a  wire  gauze 
on  a  ringstand.  Heat  the  wood.  Place  the  gauze  at  such  a 
height  above  the  flame  that  the  wood  is  heated  without  bursting 
into  a  flame.  When  the  wood  begins  to  smoke,  hold  a  lighted 
match  above  it.  The  flame  formed  is  due  to  the  burning  of 
the  volatile  substances  driven  off  from  wood  by  the  heat.  What 
change  takes  place  in  the  wood  ? 

The  substance  left  is  charcoal.  Apply  a  flame  to  it  and  see 
if  it  will  burn.  How  does  the  burning  differ  from  that  of  the 
volatile  substances  ? 

2.  In  a  similar  way  try  soft  coal,  using  a  piece  about  as  large 
as  the  end  of  your  finger. 

3.  Repeat  the  experiment,  using  hard  coal.     What  difference 
do  you  note  in  the  burning  of  the  two  coals?  The  substance 
left  after  the  first  heating  is  coke.     Will  this  burn  ? 


HZATIXG  THE   H3ME 


Means  of  starting  fires.  In  the  early  times  fires  were 
kindled  by  rubbing  two  sticks  together.  A  great  improve- 
ment was  made  on  this  method  when  sparks  were  formed  by 
striking  a  flint  against  an  iron  ore,  called  pyrites.  This 
method  was  commonly  used  till  a  little  less  than  a  century 
ago,  when  matches  were  first  made.  When  a  match  is  drawn 
across  a  rough  surface,  the  friction  generates  enough  heat  to 
set  fire  to  the  substance  on  the  tip  of  the  match,  which  then 
ignites  the  wood.  Sulfur  and 
phosphorus  have  been  com- 
monly used  because  they 
ignite  at  a  low  temperature. 
With  these  is  usually  mixed 
some  compound  that  con- 
tains oxygen,  so  that  the  sul- 
fur will  burn  more  readily. 
Until  recently  yellow  phos- 
phorus was  one  of  the  sub- 
stances commonly  used  to  tip 
matches.  This  is  a  dangerous 
element  to  handle  and  has  a 
very  injurious  effect  on  the 
people  who  make  the  matches, 


FIG.  4.  —  Primitive  method  of  making 
fire  by  friction. 


causing  a  disease  of  the  bones  which  usually  proves  serious. 
The  use  of  this  kind  of  phosphorus  has  been  forbidden  by 
law,  and  in  its  place  a  harmless  compound  of  phosphorus  is 
now  used. 

In  safety  matches  the  harmless  red  phosphorus  is  used. 
This  is  placed  on  a  rough  striking  surface  so  that  the  match 
can  be  ignited  only  by  rubbing  it  on  this  specially  prepared 
surface.  These  are  much  less  dangerous  than  the  ordinary 
match,  as  there  is  less  danger  of  accidental  fires,  such  as 
may  occur  when  mice  gnaw  matches  and  ignite  them.  While 
it  may  be  a  little  more  trouble  to  use  safety  matches,  this  is 
more  than  repaid  by  the  lessened  danger  from  fires. 


1 6  SCIENCE  OF  HOME  AND   COMMUNITY 

LABORATORY  EXERCISE  2 

Purpose.     To  compare  safety  matches  and  ordinary  matches. 

Apparatus.     Safety  matches,  ordinary  matches. 

Directions.  Notice  the  parts  of  an  ordinary  match.  How 
does  a  safety  match  differ  ?  Light  an  ordinary  match  and  note 
the  order  in  which  each  part  burns.  Do  the  same  with  a  safety 
match.  Try  to  light  each  kind  of  match  on  an  ordinary  board 
surface.  What  difference  do  you  find?  What  advantage  has 
the  safety  match  ? 

SUPPLEMENTARY   QUESTIONS  FOR   CLASS   DISCUSSION 

1.  Why  are  fireplaces  still  used ? 

2.  What  advantages  has  electricity  as  a  means  of  heating  ? 

3.  Why  is  the  stove  superior  to  the  fireplace  as  a  means  of 
heating  ? 

4.  What  principles  of  physics  are  applied  in  each  of  the 
methods  used  in  heating  our  homes  ? 

5.  What  are  the  chief  differences  between  the  hot  water  and 
the  steam  methods  of  heating  ? 

REFERENCE 

Barber,  First  Course  in  General  Science,  Henry  Holt  and  Com- 
pany, New  York  City.     Chap.  2. 


CHAPTER  II 
VENTILATING  THE  HOME 

1 .  What  are  the  essentials  for  a  good  system  of 
ventilation  ? 

2.  From  the  standpoint  of  the  ventilation  pro 
vided  which  is  the  best  heating  system  ? 

By  ventilation  is  meant  the  keeping  of  the  air  in  which  we 
live  in  such  a  condition  that  it  will  be  healthful  to  our  bodies. 
The  problems  of  heating  and  ventilating  the  home  should 
be  considered  together,  because  the  method  of  ventilation 
depends  on  the  method  of  heating  and  should  be  arranged 
for  at  the  time  that  the  heating  system  is  put  in.  Much 
can  be  done  later  to  ventilate  the  house,  however,  even  if 
no  provision  was  made  for  it  when  the  house  was  built. 

DEMONSTRATION  5 

Purpose.     To  study  the  composition  of  air. 

Apparatus.     Candle,  cork,  plate,  tumbler,  limewater. 

Directions,  i..  Get  a  cork  stopper  a  little  larger  than  the 
diameter  of  a  candle.  Cut  off  a  piece  about  half  an  inch  thick 
from  the  large  end.  In  the  center  cut  a  hole  big  enough  to 
receive  a  short  candle  about  an  inch  long.  Float  this  in  a  plate 
full  of  water.  The  experiment  can  be  seen  better  if  a  few  drops 
of  red  ink  are  added  to  the  water.  Light  the  candle  and  after 
it  is  burning  well,  invert  the  glass  tumbler  over  it.  Allow  to 
stand  for  a  while  after  the  candle  goes  out.  Why  does  the 
candle  go  out?  What  happens  to  the  water  in  the  tumbler? 
The  water  rises  to  take  the  place  of  the  oxygen  used  by  the 
c  17 


l8  SCIENCE  OF  HOME  AND   COMMUNITY 

candle.     The  gas  left  in  the  tumbler  is  nitrogen.     What  are  the 
proportions  of  oxygen  and  nitrogen  ? 

2.  To  show  the  presence  of  carbon  dioxid,  pour  some  lime- 
water  into  a  dish  and  allow  it  to  stand  for  an  hour  or  two.     The 
white  coating  that  forms  on  the  surface  of  the  water  shows  the 
presence  of  carbon  dioxid. 

3.  To  show  the  presence  of  water  in  the  air.     Bring  into  the 
schoolroom  a  metal  cup  containing  a  mixture  of    ice  and  salt. 
What  is  the  source  of  the  water  that  condenses  on  the  outside 
of  the  cup  ? 

DEMONSTRATION  6 

Purpose.  To  learn  how  the  air  we  breathe  out  differs  from 
the  air  we  breathe  in. 

Apparatus.     Thermometer,  limewater,  straw,  bicycle  pump. 

Directions,  i.  Breathe  on  the  bulb  of  a  thermometer  and 
compare  the  temperature  with  that  of  the  room. 

2.  Pour  some  limewater  into  a  test  tube  and  blow  through 
it  by  means  of  a  straw  or  glass  tube.     Pour  limewater  in  another 
tube  and  force  air  through  by  means  of  a  bicycle  pump.    Which 
solution  gets  the  milkier  ?     What  does  this  show  ? 

3.  Breathe  on  a  window  pane.     What  do  the  results  show  ? 

4.  Remove  the  covers  of  two  quart  canning  jars.     Allow  one 
jar  to  stand  outdoors.       Have  a  pupil  breathe  into  the  other 
by  means  of  a  glass  tube.     Screw  the  covers  on  both  jars  tightly 
and  let  them  stand  in  a  warm  place  for  a  day  or  two.     Just 
after  the  children  have  come  in  from  outdoors,  have  the  pupil 
who  breathed  into  the  bottle  smell  of  the  air  in  both  bottles. 
What  difference  is  noted  ?     What  does  this  experiment  show  ? 

5.  What  four  changes  have  taken  place  in  the  air  we  breathe 
out? 

Breathing.  The  air  is  made  up  of  about  one  fifth  oxygen, 
four  fifths  nitrogen,  a  small  fraction  of  one  per  cent  of  carbon 
dioxid,  besides  minute  quantities  of  other  gases ;  and  it  also 
contains  varying  amounts  of  invisible  water  vapor.  In 
the  process  of  breathing,  the  air  is  taken  into  the  lungs,  and 


VENTILATING  THE  HOME  19 

the  oxygen  is  taken  by  the  blood  to  all  parts  of  the  body. 
Here  it  unites  with  the  food  that  has  been  digested  and 
absorbed,  and  burning  takes  place  slowly,  in  much  the  same 
way  that  coal  and  wood  burn  in  the  stove,  only  much  less 
rapidly.  As  a  result  of  this  burning,  the  body  is  kept  warm 
and  power  is  given  to  use  the  muscles.  In  this  process  of 
burning,  carbon  dioxid  is  formed  and  carried  back  by  the 
blood  to  the  lungs,  from  which  it  is  exhaled.  As  a  result  of 
this  process  of  breathing,  the  oxygen  in  the  air  has  been  re- 
duced from  21  per  cent  to  16  per  cent,  and  the  carbon  dioxid 
increased  from  one  twenty-fifth  of  one  per  cent  to  about  4  per 
cent ;  and  there  has  been  also  an  increase  in  the  amount  of 
water. 

The  ill  effects  of  lack  of  ventilation.  The  ill  effects  of 
lack  of  ventilation,  as  frequently  shown  in  crowded  rooms 
and  lecture  halls,  are  well  known.  Drowsiness,  fatigue, 
lack  of  attention,  headache,  and  a  general  feeling  of  dis- 
comfort are  the  results.  Frequent  colds  and  similar  ail- 
ments are  the  common  results  in  winter  of  lack  of  proper 
ventilation.  Likewise,  the  ill  effects  on  those  who  are 
obliged  to  work  for  long  periods  of  time  in  poorly  ventilated 
rooms  are  shown  on  every  hand,  especially  by  contrast  with 
those  who  work  outdoors.  There  is  a  tendency  toward  a 
general  undermining  of  the  health,  which  may  develop  into 
tuberculosis  and  other  lung  troubles,  while  those  who  are 
much  in  the  open  are  healthier  and  much  less  likely  to  con- 
tract these  diseases. 

Chemical  causes  of  ill  effects.  In  order  to  know  how  to 
ventilate  properly,  we  need  to  know  what  are  the  causes  of 
these  ill  effects,  so  that  we  may  know  what  to  seek  and  what 
to  avoid.  Two  classes  of  causes  have  been  proposed  at 
various  times,  the  chemical  and  the  physical.  As  the  air 
undergoes  chemical  changes  in  the  process  of  breathing,  the 
early  theory  was  that  the  injurious  effects  of  bad  air  were 
due  to  a  lack  of  oxygen  or  to  an  excess  of  carbon  dioxid. 


20  SCIENCE   OF  HOME   AND    COMMUNITY 

But  experiments  have  shown  that  neither  of  these  is  the 
cause,  since  under  ordinary  conditions  practically  all  air 
contains  enough  oxygen  for  breathing,  and  practically  no 
air  contains  enough  carbon  dioxid  to  be  injurious.  Another 
explanation  was  that  there  were  tiny  organic  particles  given 
off  in  breathing  which  produced  the  ill  effects ;  but  experi- 
ments seem  to  show  that  these  are  not  the  cause ;  but  dis- 
agreeable odors,  due  to  particles  given  off  from  the  body, 
from  decaying  teeth,  and  from  clothing,  render  the  air  very 
unpleasant  and  may  at  times  produce  injurious  results. 

Physical  causes  of  ill  effects.  The  cause  for  the  ill  effects 
of  poor  ventilation  is  thus  seen  not  to  lie  in  the  lack  of  chemical 
purity  of  the  air,  but  must  be  sought  in  its  physical  conditions. 
Ventilation  is  not  merely  a  matter  of  breathing  alone,  but 
also  a  matter  of  the  reaction  of  the  skin  to  the  air  with  wrhich 
it  is  in  constant  contact. 

Recent  experiments  seem  to  show  that  in  seeking  the 
essentials  of  ventilation,  we  should  consider  the  effect  of  the 
air  on  our  skin  rather  than  the  effect  of  the  air  we  breathe 
on  our  lungs. 

How  the  body  controls  its  temperature.  In  order  to  under- 
stand what  is  needed  for  ventilation,  one  needs  to  know  some- 
thing of  the  part  that  the  skin  plays  in  the  control  of  the  heat 
of  the  body.  Heat  is  produced  in  the  body  by  the  oxidation 
of  food.  The  temperature  of  the  body  is  kept  constant, 
about  98  degrees,  and  the  body  is  provided  with  means  by 
which  this  temperature  is  automatically  kept  uniform .  There 
are  two  methods  by  which  the  body  loses  heat,  first  by  send- 
ing large  quantities  of  blood  to  the  surface  of  the  skin,  where 
it  is  cooled ;  and  second,  by  the  evaporation  of  water  from 
the  pores  of  the  skin,  in  what  is  called  perspiration.  If  the 
body  is  too  warm,  the  arteries  in  the  skin  open  wide  and 
thus  allow  large  amounts  of  blood  to  come  to  the  skin,  where 
cooling  takes  place ;  and  the  sweat  glands  increase  their 
activity  in  evaporating  water.  On  the  other  hand,  if  the 


VENTILATING  THE  HJME  21 

body  is  too  cool,  the  arteries  contract  and  less  blood  is  sent 
to  the  skin,  and  the  activity  of  the  sweat  glands  is  lessened. 

The  ill  effects  of  lack  of  ventilation  are  due  largely  to 
interference  with  this  heat-regulating  mechanism.  Recent 
experiments  show  that  these  ill  effects  are  due  chiefly  to 
four  causes :  (i)  lack  of  air  currents,  (2)  unpleasant  odors, 
(3)  too  high  a  temperature,  (4)  too  little  or  too  much  moisture 
in  the  air. 

Essentials  of  ventilation.  A  proper  system  of  ventila- 
tion should  therefore  do  these  things  : 

1.  It  should  furnish  a  gentle  current  of  air. 

2.  It  should  change  the  air  so  as  to  keep  it  free  from  dis- 
agreeable odors. 

3.  It  should  heat  this  air  to  the  proper  temperature,  not 
to  exceed  70  degrees. 

4.  It  should  add  moisture  to  bring  the  air  up  to  the  proper 
degree  of  humidity,  from  50  to  60  per  cent. 

Air  currents.  In  order  to  meet  the  first  and  second  con- 
ditions, each  room  in  the  house  should  have  two  openings, 
one  by  which  the  fresh  air  may  enter  and  another  by  which 
the  used  air  may  leave.  The  inlet  for  fresh  air  may  be  pro- 
vided by  means  of  registers  connecting  with  pipes  which 
lead  to  the  fresh  air  supply  heated  by  the  furnace.  The 
outlet  for  the  used  air  may  be  provided  by  means  of  a  fire- 
place flue,  with  which  each  room  may  be'  connected  by  a 
short  pipe,  or  the  outlet  may  be  provided  directly  by  the  open 
fireplace  itself.  A  change  of  air  may  also  be  brought  about 
through  the  use  of  windows  and  doors. 

The  common  notion  that  drafts  are  injurious  is  a  mistaken 
one,  as  they  are  essential  to  good  ventilation.  You  do  not 
take  cold  when  out  in  the  wind  if  you  are  properly  clothed. 
When  sitting  indoors,  it  is  well  to  guard  against  exposing  a 
small  part  of  the  body  to  a  very  cold,  strong  draft;  but 
some  motion  of  air  is  essential  to  our  comfort  and  health. 
If  there  is  no  movement  of  air,  the  layer  of  air  next  to  the 


22  SCIENCE  OF  HOME  AND   COMMUNITY 

skin  becomes  warm  and  saturated,  and  so  retards  further 
evaporation  and  loss  of  heat,  and  the  body  becomes  un- 
comfortably warm. 

Colds  and  similar  ailments,  which  are  so  common  during 
the  winter,  are  not  due  usually  to  exposure  to  drafts,  as  is 
often  thought,  but  are  caused  generally  by  the  unhealthful 
conditions  that  too  often  exist  indoors  during  the  cold  season ; 
hot,  dry,  motionless  air.  The  remedy  for  these  ills  is  to  re- 
move the  conditions  that  cause  them. 


DEMONSTRATION  7 

Purpose.  To  learn  the  conditions  necessary  for  a  change 
of  air  in  ventilation. 

Apparatus.  Candle,  lamp  chimney  with  even  top,  two 
matches,  cardboard. 

Directions,  i.  Light  the  candle,  place  the  chimney  over  it. 
Why  does  the  candle  go  out? 

2.  Light  the  candle  again.     On  each  side,  place  a  match. 
On  the  matches  place  the  chimney  and  cover  the  top  with  the 
cardboard.     Why  does  the  candle  go  out  now  ? 

3.  Repeat,  the  previous  experiment,  except  that  the  card- 
board is  not  placed  over  the  chimney.     Why  does  the  candle 
continue  to  burn? 

4.  What  do  these  experiments  show? 

Temperature.  If  the  temperature  is  too  high,  the  body 
makes  extra  exertion  by  means  of  the  sweat  glands  and 
blood  vessels  to  lower  the  temperature.  As  a  result  the 
blood  is  drawn  to  the  surface  from  other  parts  of  the  body, 
and  even  then  the  body  temperature  may  not  be  kept  down 
to  the  proper  level.  One  of  the  most  common  causes  of  ill 
effects  from  poor  ventilation  is  too  high  a  temperature.  It 
has  been  proved  that  the  most  healthful  temperature  for 
the  living  rooms  is  between  65  and  70  degrees.  When  the 
temperature  becomes  higher  than  70,  it  produces  feelings 


VENTILATING   THE   HOME  23 

of  discomfort,  and  makes  work  more  difficult.  The  tem- 
perature at  which  one  feels  comfortable  depends  on  the 
humidity.  With  the  low  degree  of  humidity  usually  found 
in  our  houses,  about  68  degrees  is  the  best  temperature. 
But  if  enough  moisture  is  added  to  raise  the  humidity  to 
50  or  60  per  cent,  one  will  feel  just  as  comfortable  at  65 
degrees.  The  best  temperature  also  depends  on  the  occu- 
pation and  dress  of  the  people  living  in  the  room. 

Thermometer.  The  temperature  may  be  easily  watched 
by  means  of  a  thermometer.  This  consists  of  a  glass  tube 
with  a  very  small  bore  and  a  bulb  at  one  end  filled  with  mer- 
cury, or  some  colored  liquid,  usually  alcohol,  which  does 
not  freeze  at  ordinary  temperatures.  In  making  a  ther- 
mometer, the  air  is  removed  from  the  bore  above  the  liquid, 
so  that  there  is  nothing  left  to  interfere  with  the  motion  of 
the  liquid.  Heat  causes  the  liquid  to  expand  and  rise  in 
the  bore,  which  is  marked  off  into  degrees.  In  the  common 
Fahrenheit  thermometer,  the  freezing  point  of  water  is 
marked  32  degrees  and  the  boiling  point  212  degrees,  and  the 
space  between  is  divided  into  180  degrees.  In  the  Centi- 
grade thermometer  the  freezing  point  is  marked  o,  and  the 
boiling  point  100  degrees,  and  the  space  between  is  divided 
into  100  degrees.  The  Centigrade  is  much  more  convenient 
and  is  widely  used  in  Europe  for  general  purposes  and  for 
scientific  work  in  this  country. 

LABORATORY  EXERCISE  3 

Purpose.     To  study  and  test  thermometers. 

Apparatus.  Fahrenheit  thermometer,  Centigrade  thermom- 
eter, beaker  or  tumbler,  ice. 

Directions,  i.  Make  drawings  side  by  side  of  a  Fahrenheit 
and  of  a  Centigrade  thermometer.  In  each  drawing  mark  the 
following  points :  the  freezing  point  of  water  ;  the  boiling  point 
of  water  (this  may  not  appear  on  some  thermometers) ;  the 
temperature  of  the  body  (hold  finger  on  bulb  or  breathe  on 


24  SCIENCE  OF  HOME  AND   COMMUNITY 

it — the  result  will  be  only  approximate  as  the  liquid  will  not 
rise  quite  to  the  body  temperature) ;  the  proper  living  tempera- 
ture of  the  schoolroom  in  winter. 

Into  how  many  degrees  is  the  space  between  the  freezing 
and  boiling  points  marked  on  each  scale  ?  What  advantage  do 
you  think  the  Centigrade  scale  has  over  the  Fahrenheit?  Do 
you  see  any  disadvantage  ? 

2.  The  thermometers  found  in  houses  are  often  incorrect. 
Bring  yours  from  home  so  that  you  can  test  it.  Place  the  end 
of  the  thermometer  in  a  tumbler  and  fill  the  tumbler  with  cracked 
ice.  Allow  it  to  stand  till  the  water  from  the  melted  ice  covers 
the  bulb,  and  the  liquid  in  the  thermometer  falls  no  lower. 
Record  the  reading.  The  correct  reading  is  32.  Hang  up  your 
thermometer  beside  a  tested  chemical  one  furnished  by  the 
instructor.  Note  the  difference.  The  average  of  this  difference 
and  of  the  error  at  the  freezing  point  may  be  taken  as  the  cor- 
rection to  be  made  in  using  your  thermometer. 

Humidity.  If  the  air  is  too  moist,  evaporation  in  the  skin 
takes  place  too  slowly  and  the  body  becomes  too  warm.  If 
the  air  contains  too  little  moisture,  evaporation  takes  place 
too  rapidly.  The  lack  of  moisture  in  the  heated  air  in  our 
homes  in  winter  has  an  injurious  effect  on  the  nose  and  throat. 
As  this  dry  air  passes  over  the  membrane  lining  the  nose 
and  throat,  it  causes  an  excessive  amount  of  evaporation 
from  these  surfaces,  which  become  dry,  parched,  and 
irritated.  As  a  result  they  afford  a  lodging  place  for  germs, 
and  we  become  more  easily  subject  to  colds  and  other 
diseases  of  the  throat  and  nose.  Furthermore,  these  mem- 
branes are  not  able  to  do  so  well  their  ordinary  work  of 
filtering  the  air  of  impurities. 

This  extreme  dryness  found  indoors  during  the  winter 
produces  an  artificial  and  unnatural  condition  because  it 
is  such  a  contrast  to  the  natural  condition  found  outdoors. 

The  amount  of  moisture  in  the  air  is  measured  in  terms 
of  per  cent.  When  the  air  is  saturated  (that  is,  holds  all  it 
can,  as  just  before  a  rain),  the  humidity  of  the  air  is  said  to 


VENTILATING  THE  HOME  25 

be  100  per  cent.  If  it  holds  one  half  as  much  moisture 
as  it  could  contain,  the  humidity  is  said  to  be  50  per  cent. 
Outdoors  the  humidity  ranges  from  65  to  75  per  cent  or 
more.  Indoors  during  the  winter  in  the  ordinary  heated 
room,  it  is  found  that  the  humidity  is  very  low,  ranging 
from  20  to  30  per  cent. 

During  the  winter  the  air  taken  into  the  heating  system 
from  outdoors  is  very  cold,  and  as  it  is  heated,  its  power  to 
hold  more  moisture  increases  rapidly,  doubling  for  about 
each  change  of  20  degrees :  thus  air  which  at  a  temperature 
of  30  degrees  may  be  half  saturated,  at  a  temperature  of 
70  degrees  will  be  only  about  one  eighth  saturated,  and  hence 
be  very  dry  and  possess  great  absorbing  power.  This 
humidity  may  be  raised  by  introducing  water  into  the  hot- 
air  chamber  in  the  cellar.  Many  of  the  water  pans  often 
found  in  hot-air  furnaces  are  worthless,  because  they  do  not 
add  enough  moisture  to  affect  the  humidity  appreciably. 

In  order  to  furnish  enough  moisture  for  an  ordinary  house, 
from  one  to  two  quarts  of  water  should  be  evaporated  hourly. 
There  are  now  being  sold  on  the  market  instruments  called 
humidifiers,  which  can  be  used  to  supply  the  necessary  water. 

DEMONSTRATION  8 

Purpose.     To  find  the  humidity  of  the  room. 

Apparatus.     Two  thermometers,  or  a  sling  psychrometer. 

Directions,  i.  Fasten  a  piece  of  soft  muslin  cloth  around  the 
bulb  of  one  of  the  thermometers,  and  allow  the  other  end  of  the 
cloth  to  hang  in  a  bottle  filled  with  water.  Hang  another 
thermometer  beside  this.  Fan  the  bulbs  vigorously  for  a  short 
time,  then  look  at  the  reading  of  the  wet  bulb.  Continue  to 
fan  until  the  mercury  in  the  wet  bulb  ceases  to  go  any  lower. 
Then  take  the  reading  of  both  the  thermometers.  A  slight 
difference  means  a  moist  air.  A  large  difference  means  a  dry 
air.  The  per  cent  of  humidity  may  be  found  from  the  table  in 
the  appendix,  page  555.  For  example,  if  the  difference  between 
the  two  thermometers  is  16  degrees,  and  the  reading  of  the  dry 


26 


SCIENCE  OF  HOME  AND  COMMUNITY 


bulb  is  70  degrees,  the  figure  opposite  16  and  under  70  gives  the 
per  cent  of  humidity,  in  this  case  33.  Find  the  humidity  of  the 
air  outdoors. 

2.  If  a  sling  psychrometer  is  available,  the  test  can  be  made 
more  quickly  and  accurately. 

Comparison  of  heating  systems.  We  may  now  examine 
the  various  systems  of  heating  with  reference  to  the  provision 
they  make  for  ventilation.  No  system  which  fails  to  make 
some  such  provision  should  receive  serious  consideration. 


•Sfeam  or  Jfoi  Water 
FIG.  5.  —  A  method  of  ventilation  in  steam  and  hot- water  systems. 

The  hot- water  and  steam  heating  systems,  as  ordinarily 
installed  with  radiators  in  each  room,  are  the  poorest,  as  no 
provision  is  made  for  change  of  air.  The  hot-air  furnace, 
when  fresh  air  is  taken  from  outside,  is  preferable  as  it  pro- 
vides for  a  change  of  air.  If  only  one  opening  is  provided, 
—  that  is,  the  register  where  the  hot  air  enters,  —  some 
ventilation  is  provided,  since  some  air  is  forced  out  around 
the  windows ;  but  in  the  best  systems,  another  opening  to  a 
flue  in  the  chimney  is  provided  by  means  of  which  the  used 
air  is  taken  away. 


VENTILATING  THE  HOME 


If  properly  installed,  the  hot-water  system  is  probably 
the  best.  To  provide  for  change  of  air,  coils  of  pipe  are 
placed  in  the  basement.  Fresh  air  is  led  from  outdoors  over 
these  pipes,  where  it  is  heated.  It  can  then  be  distributed 
to  the  rooms  above  by  means  of  hot-air  pipes,  in  a  manner 
similar  to  that  used  with  the  hot-air  furnace.  This  is  su- 
perior to  the  hot-air  furnace  for  two  reasons :  first,  because 
the  air  does  not  become  so  intensely  heated  and  dried,  and 
second,  because  the  temperature  can 
more  easily  be  controlled  and  kept 
down  in  the  mild  weather  of  late  fall 
and  early  spring.  It  also  has  this  sec- 
ond advantage  over  the  steam  system. 
Ventilation  may  also  be  secured  by 
bringing  the  air  directly  from  outdoors 
and  allowing  it  to  pass  over  a  radiator. 
(See  figure  6.)  As  ordinarily  installed 
the  hot-air  furnace  is  the  best  from 
the  standpoint  of  health,  provided  that 
air  is  taken  from  outdoors. 

The  open    fireplace    provides  good 
ventilation,  as  air  passes  up  the  chim- 
ney and  fresh  air  is  drawn  in  from  around  the  windows  and 
doors.     The  stove  provides  ventilation  in  the  same  way. 

Oil  stoves  and  gas  stoves  are  both  unhealthful,  as  they 
draw  the  supply  of  oxygen  from  the  air  and  give  off  all  their 
waste  products  into  the  same  room.  As  there  is  no  provision 
for  removing  it,  the  air  soon  becomes  filled  with  these 
products,  some  of  which  have  a  disagreeable  odor. 

HOME  PROJECT  2 

Purpose.     To  learn  if  your  home  is  properly  ventilated. 

Directions,  i.  Is  the  air  kept  in  motion?  Light  a  piece 
of  punk,  or  cloth,  or  a  joss  stick  and  hold  it  in  various  parts  of 
the  room  and  at  different  heights  from  the  floor  and  notice  the 


FIG.  6.  —  Ventilation  at 
the  radiator. 


28 


SCIENCE  OF  HOME  AND   COMMUNITY 


direction  of  air  currents  as  shown  by  the  smoke.  Make  a 
drawing  of  the  room  and  show  the  direction  of  currents  by 
means  of  arrows.  Open  some  windows  and  test  again  for  air 
currents.  Find  out  which  combination  of  open  windows  gives 
the  best  circulation  of  air. 

2.  Is  a  change  of  air  provided?     When  you  first  come  in 
from  outdoors  do  you  detect  odors  in  the  room?     Are  there 
any  openings  through  which  air  enters  the  room?     Does  this 
air  come  from  outdoors,  from  the  cellar,  or  is  it  return  air  taken 
from  the  room?     Are  there  any  openings  where  the  impure  air 
can  escape? 

3.  Is  the  room  kept  at  the  proper  temperature  (from  68  to 
70)  ?     Read  the  thermometer   several   times    during   the    day. 
Place  it  in  different  parts  of  the  room  and  at  different  heights 
from  the  floor  and  take  the  readings.     Make  a  record  of  all  the 
readings  in  a  table  like  the  following. 


TEMPERATURE 

TIME  OF  DAY 

HEIGHT  OF  THERMOM- 
ETER FROM  FLOOR 

LOCATION  WITH  REFER- 
ENCE TO  SOURCE  OF  HEAT 

4.  Is  the  proper  degree  of  humidity  maintained  (from  50  to  60 
per  cent)  ?  Determine  the  per  cent  of  humidity,  using  the  method 
explained  in  demonstration  8.    Find  also  the  humidity  outdoors. 

5.  Which  of  the  four  essentials  of  ventilation  are  provided 
in  your  home?     Which  ones  are  not  provided?     What  can  be 
done  to  provide  those  essentials  that  are  lacking  ? 

Ventilation  by  windows.  Unfortunately  in  many  of  our 
homes  no  special  provision  was  made  for  ventilation  when 
the  house  was  built,  so  we  must  plan  our  ventilation  as  best 


VENTILATING  THE   HOME 


29 


we  can  by  means  of  doors  and  windows.  A  certain  amount 
of  ventilation  takes  place  through  the  walls  of  houses  and 
around  the  windows  and  doors.  When  a  system  of  hot-air 
heating  is  used  by  means  of  which  fresh  air  is  forced  into  the 
room,  other  air  must  be  forced  out  through  these  cracks  and 
this  provides  some  ventilation,  sufficient  perhaps  for  a  small 
family  but  not  enough  for  a  schoolroom.  In  the  hot- water 
or  steam  system,  when  radiators  are  placed  in  the  rooms 
with  no  provision 
for  bringing  in  fresh 
air,  the  amount  of 
ventilation  brought 
about  by  means  of 
the  cracks  around 
the  windows  is  in- 
adequate. This  is 
especially  true  of  our 
modern  houses  which 
are  made  more  com- 
pletely air  tight  than 
formerly.  Often  too 
in  northern  climates 


FIG.  7.  —  Ventilation  by  window. 


they  are  provided  with  storm  windows,  which  tend  to  keep 
out  the  fresh  air  that  might  otherwise  have  entered. 

Ventilation  may  be  secured  by  opening  windows  on  differ- 
ent sides  of  a  room,  and  a  board  may  be  placed  in  front  of  a 
window  to  break  the  strength  of  the  wind.  One  excellent 
way  of  providing  ventilation  without  lowering  the  tempera- 
ture of  the  room  is  to  fit  a  frame  to  the  lower  window  like  a 
mosquito  screen,  so  that  the  window  may  be  lifted  and  the 
frame  placed  under  it.  This  may  be  made  any  height,  and 
covered  with  ordinary  cotton  cloth.  This  allows  the  fresh  air 
to  enter  but  prevents  the  room  from  being  suddenly  cooled, 
as  the  cloth  does  not  lose  heat  much  faster  than  the  glass  in 
the  window. 


30  SCIENCE  OF  HOME  AND   COMMUNITY 

Ventilation  of  sleeping  room.  Special  attention  should 
be  given  to  the  ventilation  of  our  sleeping  rooms,  even  in 
the  coldest  weather.  Fresh  air  should  be  provided  by  open- 
ing the  windows  wide,  and  in  cold  weather  we  may  keep  our- 
selves comfortable  by  extra  blankets.  In  cold,  windy  weather, 
strong  drafts  may  be  avoided  by  placing  a  chair  with  a  towel 
or  piece  of  cloth  over  it  in  front  of  the  window ;  or  a  board 


FIG.  8.  —  Getting  fresh  air  at  night. 

may  be  placed  across  the  bottom  of  the  window  in  such  a 
way  that  the  air  will  strike  this  and  be  deflected  over  the 
top  into  the  upper  part  of  the  room.  Or  a  screen  mentioned 
in  the  previous  paragraph  may  be  used.  In  order  to  get  the 
full  benefit  of  the  ventilation  furnished  by  the  window  in 
figure  8,  it  would  be  better  for  the  sleeper  if  he  slept  with  his 
head  at  the  foot  of  the  bed,  or  if  the  bed  were  turned  end 
for  end. 


VENTILATING  THE  HOME  31 

HOME  PROJECT  3 

Purpose.     To  make  a  ventilating  screen. 

Directions.  Make  a  ventilating  screen  to  fit  your  bedroom 
windows  for  use  in  cold  weather.  Follow  the  directions  given 
on  page  29.  Try  it  and  see  if  it  proves  satisfactory. 

The  sleeping  porch  is  the  best  means  for  procuring  perfect 
ventilation  while  asleep.  Even  after  the  house  has  been 
built,  a  sleeping  porch  can  be  easily  added  to  it.  In  most 
sections  of  our  country  this  can  be  used  all  the  year  round. 
And  even  in  the  northern  portions  it  can  be  used  three 
fourths  of  the  year.  From  the  standpoint  of  health,  a  sleep- 
ing porch  is  one  of  the  most  profitable  investments  that  can 
be  made. 

HOME  PROJECT  4 

Purpose.     To  make  a  sleeping  porch. 

Directions.  Talk  the  matter  over  with  your  parents  and 
see  if  it  is  possible  to  arrange  some  place  where  you  can  sleep 
out  at  least  during  the  warmer  months  of  the  year.  There  may 
be  some  porch  that  can  be  screened  and  fixed  without  much 
trouble.  A  small  sleeping  porch  can  often  be  added  to  the  house 
at  slight  expense. 


SUPPLEMENTARY   QUESTIONS   FOR   CLASS   DISCUSSION 

1.  How  does  the  air  we  breathe  out  differ  from  the  air  we 
breathe  in? 

2.  What  theories  have  been  advanced  to  explain  the  reason 
for  the  ill  effects  due  to  poor  ventilation  ?     Which  is  the  correct 
one? 

3.  How  does  the  body  control  its  temperature? 

4.  Are  the  essentials  of  ventilation  provided  in  your  home? 
In  the  schoolroom  ? 

5.  What  is  the  principle  involved  in  the  thermometer? 

6.  What  is  the  relation  of  humidity  to  ventilation  ? 


32  SCIENCE  OF  HOME  AND  COMMUNITY 

7.  Heated  air  contains  the  same  amount  of  water  that  it  did 
when  cold.     Why  is  the  per  cent  of  humidity  so  much  lower  ? 

8.  How  may  ventilation  be  secured  during  the  night  while 
asleep  ? 

REFERENCES 

Barber,  First  Course  in  General  Science,  Henry  Holt  and  Com- 
pany, New  York  City.  Chap.  6. 

Fisher  and  Fisk,  How  to  Live,  Funk  and  Wagnalls,  New  York 
City.  Chap.  i. 


CHAPTER   III 


LIGHTING   THE   HOME 

What  advantages  has  each  of  the  methods  now 
used  for  lighting  the  home  ? 

Early  means  of  lighting.  As  we  have  already  seen,  methods 
of  heating  have  gone  through  many  changes,  beginning  with 
crude  devices  used  by  primitive  people.  In  a  similar  way 
methods  of  lighting  have  undergone  many  changes,  begin- 
ning with  the  simplest  forms  used  thousands  of  years  ago. 
Probably  the  first  method  of  lighting  was  a  torch  made  by 
setting  fire  to  the  end  of  a  stick.  This  was  the 
only  means  used  for  many  hundreds  of  years. 
In  time  crude  forms  of  candles  appeared,  and 
these  were  gradually  improved  until  now  we 
have  our  modern  candle.  At  first  candles  were 
made  by  hand  by  dipping  a  string  into  melted 
tallow  and  allowing  it  to  cool,  and  then  dipping 
again  until  the  desired  size  was  obtained.  To- 
day candles  are  made  by  machinery  by  pouring 
the  melted  paraffin  into  molds,  through  the 
center  of  which  hang  strings. 

In  our  own  country  torches  were  frequently 
used  by  the  early  settlers.  Lincoln  learned  to  read  by  the 
light  of  pine  knots.  The  candle  was  very  widely  used  even 
during  the  first  half  of  the  last  century. 

Early  lamps.     Another  means  of  lighting  used  in  early 
tr^'Bs  along  with  the  torch  was  a  crude  form  of  lamp.     This 

D  33 


34  SCIENCE  OF  HOME  AND   COMMUNITY 

consisted  of  some  open  receptacle  like  a  shell,  filled  with  oil, 
in  which  was  placed  a  wick  of  some  fibrous  material.  These 
lamps  gave  a  very  weak  and  flickering  light  and  gave  off 
much  smoke.  It  was  a  long  time  before  a  chimney  was  in- 
vented. The  first  lamp  with  a  chimney  was  made  about 
one  hundred  twenty-five  years  ago  by  a  Swiss  named 
Argand. 

Various  kinds  of  oils  have  been  used.  During  the  first  half 
of  the  nineteenth  century  whale  oil  was  in  common  use  in 
this  country.  This  was  later  replaced  by  kerosene,  which 
has  been  in  use  for  only  about  fifty  years. 

The  plan  of  lighting  a  house  by  gas  carried  to  different 
rooms  through  pipes  was  first  tried  about  one  hundred 
twenty  years  ago.  A  little  less  than  a  hundred  years 
ago  gas  was  first  used  to  light  the  streets  of  an  American 
city. 

Finally  came  the  electric  light.  The  arc  lamp  for  street 
lighting  was  first  used  about  forty  years  ago.  A  little  later, 
for  use  indoors,  appeared  the  incandescent  lamp,  which  is  so 
widely  used  to-day. 

Burning  of  the  candle.  When  the  candle  is  first  lighted 
the  heat  melts  the  paraffin,  this  liquid  is  drawn  up  the  wick 
by  capillarity,  the  heat  then  changes  the  liquid  to  gas,  and 
the  gas  burns  with  a  flame.  The  elements  in  the  gas  unite 
with  the  oxygen  of  the  air,  and  gases  are  given  off,  chiefly 
carbon  dioxid  and  water  vapor.  An  ordinary  flame  consists 
of  two  parts,  a  bluish  inner  portion  and  a  yellowish  outer 
portion.  This  inner  part  consists  of  the  unburned  gas  formed 
by  heating  the  liquid.  The  outer  part  consists  of  the  burning 
gases.  The  light  of  the  flame  is  due  to  small  particles  of 
carbon  which  become  intensely  hot,  and  glow,  thus  giving 
off  light.  The  yellowish  color  is  due  to  the  presence  of  small 
quantities  of  compounds  of  a  metal  called  sodium,  which  is 
present  in  minute  quantities  even  on  the  dust  particles  of 
the  air. 


LIGHTING  THE  HOME  35 

LABORATORY  EXERCISE  4 

Purpose.     To  study  the  burning  of  a  candle. 

Apparatus.     Candle,  piece  of  glass  or  cardboard. 

Directions,  i.  Light  the  candle.  After  it  is  burning  well, 
light  a  match,  blow  out  the  candle,  and  then  quickly  hold  the 
lighted  match  about  a  half  inch  above  the  candle.  Why  does 
it  light?  Try  several  times  to  see  how  far  above  the  candle 
you  can  hold  the  match  and  have  it  light. 

2.  How  many  parts  do  you  see  in  the  candle  flame?     What 
is  happening  to  the  paraffin  near  the  wick?     Blow  out  the 
candle  flame  and  look  quickly  at  the  wick  and  feel  of  it.     What 
does  it  contain? 

3.  Press  a  piece  of  glass  or  cardboard  down  on  the  flame  and 
hold  it  so  for  a  second  or  two.     What  is  formed  on  the  glass? 
How  is  it  arranged  ? 

4.  Hold  a  match  or  toothpick  across  the  middle  of  the  flame 
till  it  begins  to  burn,  then  take  it  away  and  blow  out  the  flame 
on  the  wood.     Where  does  it  begin  to  burn  first  ? 

5.  What  do  the  last  two  experiments  show  regarding  the  hot- 
test part  of  the  flame  ? 

LABORATORY  EXERCISE  5 

Purpose.  To  find  out  what  conditions  are  needed  for  a  candle 
to  continue  burning. 

Apparatus.  Lamp  chimney  with  level  top,  limewater,  glass 
tumbler. 

Directions.  I.  Light  the  candle.  Invert  a  glass  tumbler 
over  it.  Why  does  it  go  out?  Light  the  candle  again.  In- 
vert over  it  a  canning  jar.  Does  the  candle  burn  any  longer? 
Why? 

2.  Light  the  candle.     On  each  side  place  a  match  and  on 
these  put  the  lamp  chimney.     Place  a  piece  of  cardboard  on 
the  top  of  the  chimney.     Why  does  the  flame  go  out  ? 

3.  Light  the  candle  and  place  it  on  a  piece  of  blotting  paper. 
Put  the  chimney  over  the  candle  and  hold  it  down  firmly  on  the 
blotting  paper.     Why  does  the  flame  go  out  ? 


36  SCIENCE  OF  HOME  AND   COMMUNITY 

4.  Light  the  candle  and  place  a  match  on  each  side.     On 
the  matches  place  the  chimney.     Does  the  flame  act  any  dif- 
ferently than  in  the  previous  experiments  ?     Why  ? 

5.  What  do  these  experiments  show  that  a  candle  needs  in 
order  to  keep  burning  ? 

6.  To  show  what  is  given  off  when  a  candle  burns,  place  a 
candle  about  an  inch  long  in  a  glass  tumbler.     Light  the  candle 
and  cover  the  tumbler  with  a  piece  of  cardboard.     After  the 
flame  goes   out,   quickly  remove   the  candle    and   pour  some 
limewater  into  the  tumbler.      Cover  the  tumbler   and  shake. 
The   white  substance  formed  shows   the  presence  of   carbon 
dioxid. 

Kerosen-e  lamps.  The  kerosene  lamp  marked  a  great 
advance  over  the  candle  as  it  gives  a  stronger  and  steadier 
light.  Kerosene  is  obtained  from  petroleum,  a  thick  liquid 
found  in  the  earth.  It.  contains  a  great  variety  of  sub- 
stances, which  are  separated  from  each  other  by  heating  the 
petroleum.  As  this  is  heated  the  various  liquids  present 
boil  and  are  given  off  as  gases  which  are  caught  and  cooled 
till  they  condense  to  liquids  again.  Those  which  boil  at 
the  low  temperatures  are  given  off  first.  These  gases  are 
caught  in  different  vessels  according  to  the  temperature  at 
which  they  are  given  off,  and  thus  the  various  liquids  are 
separated.  Kerosene  is  one  of  the  liquids  that  has  a  high 
boiling  point.  If  the  oil  we  burn  in  lamps  should  contain 
liquids  that  burn  at  a  low  temperature,  there  would  be 
danger  of  explosion,  so  the  government  as  a  protection 
requires  that  kerosene  shall  have  a  flashing  point  of  suffi- 
ciently high  temperature  to  be  safe  under  ordinary  con- 
ditions. The  flashing  point  is  the  temperature  at  which  a 
momentary  flash  is  formed  when  a  flame  is  brought  near  the 
oil.  The  standard  set  is  usually  about  no  degrees.  The 
temperature  at  which  a  continuous  flame  would  be  main- 
tained is  from  40  to  50  degrees  higher.  This  is  called  the 
burning  point. 


LIGHTING  THE  HOME  37 

The  principle  involved  in  the  burning  of  kerosene  is  the 
same  as  with  the  candle,  except  that  the  substance  used  is  a 
liquid  instead  of  a  solid.  The  heat  changes  this  liquid  to  a 
gas  which  burns  and  gives  off  heat  and  light.  One  feature 
which  gives  the  kerosene  lamp  a  great  advantage  over  the 
candle  is  the  use  of  a  chimney.  This  creates  a  draft  which 
furnishes  a  constant  supply  of  fresh  air  to  the  wick,  and  in- 
sures a  steady  light.  In  some  lamps  the  wick  is  made  cir- 
cular so  that  the  air  is  supplied  from  the  inside  as  well  as 
from  the  outside.  In  one  type  of  hanging  lamp,  the  wick 
and  chimney  are  placed  on  the  side,  so  that  the  light  is  thrown 
downward. 

Capillarity.  The  process  by  which  the  kerosene  rises 
through  the  wick  is  called  capillarity.  Other  illustrations 
of  capillarity  are  seen  in  the  absorption  of  ink  by  a  blotter 
and  in  the  rise  of  water  through  soils.  When  water  stands  in 
a  dish,  the  water  at  the  side  is  attracted  by  the  dish  and  rises 
slightly,  making  a  curved  surface.  If  the  container  becomes 
so  small  as  to  be  a  tube,  the  water  inside  the  tube  rises  higher 
than  the  surface  outside,  and  the  smaller  the  tube  the  higher 
the  water  rises.  The  spaces  between  the  threads  of  the 
wick  act  like  small  tubes  through  which  the  kerosene  rises. 

DEMONSTRATION  9 

Purpose.  To  study  the  structure  and  workings  of  a  kerosene 
lamp. 

Apparatus.  Ordinary  kerosene  lamp,  small  tube,  plate,  two 
pieces  of  glass  of  the  same  size,  rubber  band,  two  tumblers,  red 
ink,  lump  of  sugar,  blotting  paper. 

Directions,  i.  Study  the  structure  of  the  parts  of  the  lamp. 
What  purpose  does  each  part  serve? 

2.  Light  the  lamp.  After  it  burns  for  a  minute  blow  it  out 
and  quickly  hold  a  lighted  match  above  the  wick.  Try  several 
times  to  see  how  far  above  the  wick  the  match  can  be  held  and 
Still  light  the  wick.  What  does  this  show  ? 


3,    ,  SCIENCE  OF  HOME  AND   COMMUNITY 

3.  Light  the  wick  and  keep  the  chimney  off.     Fan  the  flame 
gently.     Put  on  the  chimney.     What  difference  does  it  make  in 
the'  flame?     Fan  the  air  near  the  chimney.     How  does  the 
effect  differ  from  that  when  the  chimney  was  off  ? 

4.  Push  a  piece  of  cloth  up  under  the  burner  and  cover  the 
small  holes  on  the  under  side.     What  happens  ?     Why  ? 

5.  The  method  by  which  the  oil  passes  up  through  the  wick 
is  called  capillarity.     A  few  simple  experiments  will  illustrate 
this.     Put  a  small  tube  in  water.     Compare  the  level  of  the 
water  inside  with  that  outside. 

Put  some  water  in  a  plate  and  add  a  little  red  ink.  Place 
two. pieces  of  glass  together  and  set  them  on  edge  in  the  plate. 
Separate  the  two  at  one  edge  and  insert  a  piece  of  toothpick 
or  match.  Keep  the  opposite  edges  touching  by  means  of  a 
rubber  band.  Hold  the  pieces  in  this  position  and  notice  how 
the  water  rises  between  the  plates.  How  do  you  explain  the 
curve  assumed  by  the  water  between  the  pieces  of  glass  ? 

Put  the  edge  of  a  piece  of  blotting  paper  in  ink  and  see  how 
far  up  the  ink  will  rise.  Hold  the  corner  of  a  lump  of  sugar  in 
water  and  note  results. 

Gas.  The  use  of  gas  marks  another  advance  in  the 
methods  of  lighting.  The  mantle  flames  give  a  stronger 
light  than  the  kerosene  lamp  ;  and  the  gas  fixtures  are  much 
more  convenient,  as  burners  can  be  placed  in  each  room  and 
connected  with  a  common  supply  of  gas. 

Two  kinds  of  gas  are  commonly  used,  coal  gas  and  water 
gas.  Coal  gas  is  made  by  heating  coal  in  an  inclosed  retort 
so  that  it  cannot  burn.  As  a  result  combustible  gases  are 
given  off.  These  are  purified  and  finally  stored  over  water 
in  large  tanks.  Large  pipes  carry  the  gas  to  various  parts  of 
the  city,  and  small  pipes  from  these  lead  to  each  house.  The 
pressure  is  kept  up  by  the  weight  of  these  tanks,  which  rise 
and  fall  according  to  the  supply  of  gas  they  contain. 

Water  gas  is  more  commonly  used.  This  is  made  by 
passing  steam  over  heated  coal.  As  a  result  hydrogen  and 
carbon  monoxid  are  formed,  both  being  gases  which  burn 


LIGHTING  THE  HOME 


39 


readily.  The  carbon  monoxid  is  a  very  poisonous  gas  and 
great  precaution  should  be  observed  in  the  use  of  water  gas, 
to  see  that  there  are  no  leaks  in  the' pipes  and  that  the  gas 
is  not  escaping  at  an  unlighted  burner. 

As  the  gas  enters  the  house,  it  first  passes  through  a  meter 
by  means  of  which  the  amount  used  is  measured.  The 
pressure  of  the  gas  moves  a  disk  back  and  forth,  which  is 
connected  with  a  mechanism  that  rotates  hands  on  a  dial. 
There  are  several  of  these  dials,  one  measuring  small  amounts, 
about  5  cubic  feet,  another  1000  cubic  feet,  another  10,000, 


P/pe  to  Burners 


Valve 


Afovab/e 


Section  through  meter 


Dial 


FIG.  10.  —  The  gas  meter. 


and  another  100,000.  By  subtracting  the  reading  fpunct 
at  any  previous  date  from  the  present  reading,  the  amount 
of  gas  used  can  be  determined. 

One  way  of  rinding  out  whether  the  gas  pipes  leak  in  the 
house  is  to  make  a  careful  reading  of  the  meter  at  night  after 
the  lights  are  turned  out  and  then  make  another  reading 
the  next  day  just  before  the  gas  is  lighted.  The  difference 
represents  the  amount  of  gas  that  has  leaked  out.  Even 
if  the  expense  involved  is  slight,  the  leakage  may  be  dan- 
gerous to  the  health  of  the  people  living  in  the  house. 

At  first,  burners  were  used,  at  which  light  was  given  off 
directly  by  the  burning  of  the  gas.  But  a  great  improve- 


40  SCIENCE  OF  HOME  AND  COMMUNITY 

ment  has  been  made  through  the  use  of  mantles,  which  give 
a  stronger  light  and  use  less  gas.  These  mantles  are  made 
of  substances  which  do  not  burn,  but  which  when  heated 
give  off  a  bright  light.  Mantles  must  be  replaced  occasion- 
ally, as  they  are  so  fragile  that  they  are  very  easily  broken. 
In  burners  that  are  equipped  with  mantles  a  special  arrange- 
ment is  made  for  admitting  a  large  supply  of  air  so  that  more 
complete  combustion  takes  place.  This  gives  a  higher 
temperature,  which  makes  the  mantles  incandescent. 

,  • 

HOME  PROJECT  5 

Purpose.  To  read  the  gas  meter  and  learn  the  cost  of  the  gas 
used. 

Directions,  i.  If  you  use  gas  in  your  home,  make  a  read- 
ing of  the  meter.  Make  a  drawing  of  the  circles  on  the  meter 
and  indicate  the  pointer  in  each  in  the  proper  position.  Record 
the  reading  of  the  meter.  Notice  how  the  gas  can  be  turned 
off  in  case  it  should  be  necessary,  as  when  gas  escapes  from  a 
broken  pipe.  One  week  later,  read  the  meter  again  and  make 
another  drawing.  Subtract  the  first  reading  from  the  second 
to  find  how  much  gas  was  used  in  a  week.  Find  the  price  of 
gas  and  compute  the  cost  of  the  gas  used  in  one  week. 

2.  In  order  to  find  out  whether  the  gas  pipes  leak,  read  the 
small  dial  called  the  test  dial,  just  after  the  gas  is  turned  off  for 
the  night.  Read  the  dial  again  the  next  day  just  before  the 
first  burner  is  lighted.  Any  difference  in  the  readings  represents 
the  amount  of  gas  that  has  leaked  from  the  pipes. 

Acetylene.  The  chief  advantage  in  the  use  of  acetylene 
gas  lies  in  the  fact  that  it  can  be  installed  for  isolated  houses 
too  far  away  from  towns  to  use  gas  or  electricity.  The  gas 
is  made  by  adding  water  to  a  solid  substance  called  calcium 
carbide.  The  generating  apparatus  is  so  arranged  that  the 
water  and  carbide  are  brought  in  contact,  the  gas  is  collected 
in  tanks,  and  the  amount  of  gas  generated  is  regulated  by 
pressure.  The  house  is  piped  as  for  gas,  and  the  pipes  are 


LIGHTING   THE   HOME 


41 


connected  with  the  tanks.  Acetylene  gas  gives  a  very 
brilliant  white  light.  Occasionally  one  hears  of  dangerous 
explosions  from  the  use  of  these  outfits. 


•Button 


LABORATORY  EXERCISE  6 

Purpose.     To  generate  acetylene. 

Apparatus.     Test  tube,  calcium  carbide. 

Directions.  Fill  a  test  tube  half  full  of  water  and  place  it 
on  a  test  tube  rack.  Drop  into  the  tube  two  or  three  small 
pieces  of  calcium  carbide.  Notice  what  happens  in  the  water. 
Stand  a  little  distance  from  the  tube  and  apply  a  lighted  match 
to  the  mouth.  Note  the  appearance  of  the  flame  due  to  the 
burning  of  the  acetylene. 

Electricity.  The  latest  advance  made  in  lighting  is  the 
use  of  electricity,  which  is  more  convenient  even  than  gas. 
When  the  current  first  enters  the  house 
it  passes  through  a  meter,  which  records 
the  amount  of  electricity  that  is  used  in 
the  house.  This  meter  has  several  dials 
and  looks  much  like  a  gas  meter.  A 
switch  is  usually  provided  so  that  the  cur- 
rent may  be  disconnected.  If  an  extra 
strong  current  should  pass  through  the 
wires,  they  would  become  heated  and 
might  set  fire  to  the  house.  To  avoid  this 
danger,  a  fuse  box  is  provided  where  the 
current  enters  the  house.  The  fuses  are 
made  of  such  materials  that  if  too  strong  a  current  passes 
through  them  they  melt.  Thus  the  circuit  is  broken  and  the 
current  does  not  pass  through  the  wires  in  the  house.  In 
wiring  the  house,  care  should  be  taken  to  see  that  the  wires 
are  properly  covered  with  some  insulator,  which,  being  a  non- 
conductor of  electricity,  will  not  permit  the  current  to  pass 
through. 


-Screw 


G/ass  fube 


-Ft/amesit 


FIG.  ii. —  Incandescent 
lamp. 


SCIENCE  OF  HOME  AND   COMMUNITY 


The  light  in  the  bulb  is  due  to  the  wires  or  filaments  coiled 
inside,  which  offer  so  much  resistance  to  the  current  that 
they  become  white  hot  and  their  glowing  produces  light. 
In  the  first  lamps  these  filaments  were  usually  made  of 
carbon,  but  now  other  elements,  such  as  tungsten,  are  being 
used  in  place  of  carbon.  (See  figures  n  and  12.)  These 
lamps  cost  more  than  carbon  filament 
lamps,  but  they  are  more  economical 
as  they  use  less  electricity  than  carbon 
in  giving  the  same  amount  of  light. 
To  prevent  these  filaments  from  unit- 
ing with  oxygen  and  "  burning  up," 
the  air  is  pumped  out  of  the  bulbs  so 
that  the  interior  of  the  bulb  is  a  partial 
vacuum.  This  accounts  for  the  loud 
report  made  when  one  breaks. 

One  pleasing  method  of  lighting  is 
called  the  indirect  method,  in  which 
a  large  shade  is  suspended  from  the 
ceiling  or  fastened  to  the  walls,  with 
the  lamps  placed  inside  of  it.  The 
lamps  cannot  be  seen  and  so  do  not  dazzle  the  eyes  ;  but  the 
shades  permit  some  diffused  light  to  pass  through,  and  some 
light  is  reflected  from  the  ceiling. 


STRONG  TIP 
TO  PREVENT 
TIP  BREAKAGE 


FIG.  12.  —  Mazda  lamp. 


HOME  PROJECT  6 

Purpose.  To  read  the  electric  meter  and  compute  the  cost  of 
electricity. 

Directions,  i.  If  you  use  electricity  in  your  home,  read  the 
meter.  Make  a  drawing  of  the  circles  showing  the  position  of 
the  pointers.  Record  the  reading. 

2.  Notice  how  you  could  cut  off  the  current  if  you  should 
wish  to.  Can  you  think  of  any  circumstances  under  which  it 
might  be  desirable  to  do  this  ? 


LIGHTING  THE  HOME  43 

3.  One  week  later,  read  again.  How  much  electricity  was 
used  in  one  week?  Find  out  the  price  of  electricity  and  com- 
pute the  cost  for  one  week. 

Comparison  of  lights.  These  different  means  of  lighting 
may  now  be  compared  to  see  which  is  the  best.  From  the 
standpoint  of  health  one  point  to  consider  is  the  effect  on 
the  air  of  the  room.  In  this  respect  the  electric  light  is  the 
best  as  it  does  not  affect  the  composition  of  the  air.  All 
other  forms  of  lighting  take  oxygen  from  the  air  and  give 
off  waste  products  into  the  air  as  a  result  of  burning.  In 
those  lamps  in  which  there  is  a  complete  burning,  as  the 
mantle  gas  lamp  and  acetylene,  only  carbon  dioxid  and 
water  are  given  off.  But  in  those  cases  where  the  burning 
is  not  complete,  as  with  the  kerosene  lamp  and  ordinary  gas 
burners,  besides  those  gases  there  are  given  off  others  which 
are  injurious  in  their  effect  on  the  health. 

Another  point  to  consider  is  the  effect  of  the  various  lamps 
on  the  eye.  Steadiness  is  an  important  requirement.  From 
this  standpoint,  the  electric  lamp,  the  acetylene  flame,  and 
the  mantle  gas  lamp  are  the  best,  as  they  give  a  steady  light. 
Next  comes  the  kerosene  lamp,  which  is  fairly  steady;  and 
poorest  of  all  are  the  candle  and  ordinary  gas  burner,  which 
give  such  a  flickering  flame  as  to  tire  the  eye. 

Glass  and  sunligjit.  To-day  our  houses  during  the  day- 
time are  brightly  lighted  by  the  sunlight  that  comes  through 
the  window  panes.  But  before  glass  was  made,  houses  were 
dark  and  dingy,  because  people  used  oiled  paper  and  isin- 
glass in  their  windows.  Glass  to-day  is  so  common  and  cheap 
that  we  perhaps  do  not  realize  what  a  great  help  it  is  to  us. 
Window  glass  is  made  of  pure  sand  and  compounds  of  the 
two  metals,  calcium  and  sodium,  lime  and  soda  being  com- 
monly used.  These  are  heated  together  at  a  very  high 
temperature  and  form  liquid  glass.  As  it  cools,  it  becomes 
pasty  and  can  be  worked  into  various  shapes. 


44  SCIENCE  OF   HOME  AND   COMMUNITY 

SUPPLEMENTARY    QULSTIONS   FOR    CLASS   DISCUSSION 

1.  What  advantages  has  the  kerosene  lamp  over  all  methods 
of  lighting  used  previously  ? 

2.  In  what  ways  are  the  burning  of  a  candle  and  of  a  kerosene 
lamp  similar?     In  what  ways  are  they  different? 

3.  Of  how  many  illustrations  of  capillarity  can  you  think? 

4.  In  what  ways  is  gas  better  than  kerosene  for  lighting  ? 

5.  In  what  ways  is  electricity  better  than  gas? 


REFERENCES 

\ 

Barber,  First  Course  in  General  Science,  Henry  Holt  and  Com- 
pany, New  York  City.  Chap.  I. 

Holland,  Historic  Inventions,  G.  W.  Jacobs,  Philadelphia. 
Chap.  14. 


CHAPTER   IV 
THE   HOME   WATER   SUPPLY 

1.  What  care  should  be  taken  to  see  that  wells 
and  other  sources  of  drinking  water  are  kept  pure  ? 

2.  What  has  the  air  to  do  with  the  working  of 
a  pump  ? 

3.  Which  is  the  best  method  of  getting  running 
water  in  the  home  ? 

Kinds  of  wells.  Dug  wells.  The  water  supply  for  the 
home  that  is  not  connected  with  a  system  of  public  water- 
works may  be  obtained  from  wells,  cisterns,  springs,  or 
brooks.  The  commonest  type  of  well  is  the  dug  well,  which 
may  be  either  shallow  or  deep.  The  most  important  con- 
sideration is  the  purity  of  the  water,  and  this  is  chiefly 
affected  by  the  surroundings  of  the  well.  A  well  drains  a 
region  in  the  form  of  an  inverted  cone  with  its  point  at  the 
bottom  of  the  well  and  its  sides  extending  out  at  varying 
angles.  There  should  be  no  cesspools,  sink  drains,  barn 
yards,  or  privies  near  enough  so  that  the  drainage  from 
them  can  reach  the  well. 

The  soil  acts  as  a  filter,  and  impure  water  as  it  passes 
through  the  soil  tends  to  become  purified,  but  after  a  while 
the  soil  becomes  clogged  with  the  impurities  which  it  collects, 
and  so  loses  its  power  to  purify  water.  When  there  is  a 
constant  source  of  impure  water,  like  a  cesspool,  near  the 
well,  the  soil  between  the  two  tends  to  become  less  effective 
as  a  filter  the  longer  it  is  used. 

45 


46 


SCIENCE  OF  HOME  AND   COMMUNITY 


The  conclusion  to  be  drawn  is  that  the  well  should  be 
located  so  far  from  possible  sources  of  impurities  that  there 
will  be  no  danger  of  pollution.  This  distance  varies  with 
different  conditions,  such  as  kind  of  soil,  the  slope  of  the  sur- 
face and  of  the  rock  strata,  and  the  depth  of  the  well.  In 
general,  however,  the  well  should  be  a  hundred  feet  from 
sources  of  impurities.  If  the  slope  of  the  surface  is  toward 


FIG.  13.  —  Danger  of  having  cesspool  and  well  too  near  together. 

the  well,  the  impurities  are  more  apt  to  find  their  way  into 
it.  But  even  when  the  surface  is  level,  the  slope  of  the  rock 
strata  beneath  may  slant  toward  the  well. 

The  well  should  be  so  constructed  as  to  prevent  surface 
water  from  draining  into  it.  The  top  portion  should  be 
bricked  down  for  six  feet  so  as  to  be  water-tight,  and  a  casing 
of  cement  or  brick  should  be  raised  about  a  foot  above  the 
surface.  The  covering  over  the  well  should  be  tight  to  pre- 
vent any  impurities  from  falling  through.  A  trough  should 
be  provided  under  the  pump  spout  to  carry  off  the  overflow 
when  the  pump  is  used.  Care  should  be  taken  to  see  that 
dirt  is  not  tracked  on  to  the  well  covering. 


THE  HOME  WATER  SUPPLY 


47 


FIG.  14.  —  The  two  figures  on  the  right  show  the  right  way  and  the  figure  on  the 
left  shows  the  wrong  way  to  construct  a  well. 


DEMONSTRATION  10 

Purpose.     To  test  the  purity  of  drinking  water. 

Apparatus.  Distilled  water,  samples  of  drinking  water  from 
several  sources,  solution  of  potassium  permanganate,  nitric 
acid,  solution  of  silver  nitrate,  two  beakers,  test  tubes. 

Directions,  i.  To  test  for  decaying  vegetable  matter. 
Pour  some  distilled  water  into  a  beaker.  Pour  the  same  amount 
of  drinking  water  into  another  beaker.  Add  to  each  beaker 
one  drop  of  potassium  permanganate  solution.  Boil  the  drink- 
ing water  for  a  few  minutes  and  allow  it  to  cool.  Compare  the 
colors  in  the  two  beakers.  If  the  color  of  the  drinking  water 
is  very  different  from  the  pinkish  tint  of  the  distilled  water, 
vegetable  impurities  are  present. 


48  SCIENCE  OF  HOME  AND   COMMUNITY 

2.  To  test  for  animal  impurities.  To  the  sample  of  water 
to  be  tested  add  a  few  drops  of  nitric  acid  and  a  few  drops  of 
silver  nitrate  and  stir.  If  the  water  becomes  milky,  animal 
impurities  are  present.  This  is  not  an  infallible  test,  because 
the  presence  of  chlorides  in  the  water  will  also  give  a  white 
precipitate. 

Bored  wells.  Sometimes  bored  wells  are  used.  This  is 
really  a  convenient  way  of  digging  a  small  well.  Soil  augers 
are  used.  The  soil  is  removed  for  a  considerable  depth 
and  the  hole  lined  with  tiling.  The  same  precautions  should 
be  observed  with  reference  to  this  well  as  for  the  dug  well. 

Driven  wells.  To  make  a  driven  well,  a  pipe  with  a  hard 
point  is  driven  into  the  ground  till  a  layer  of  soil  is  reached 
that  has  a  constant  supply  of  water.  The  pipe  is  removed 
and  the  driving  point  is  replaced  with  a  filtering  point  covered 
with  a  sieve,  which  allows  the  water  to  enter  but  prevents 
the  dirt  from  filling  the  pipe.  The  pipe  is  then  driven  down 
again.  Under  favorable  conditions  these  wells  may  prove 
satisfactory.  The  chief  objections  are  that  the  amount  of 
water  that  can  be  pumped  at  one  time  is  small  and  that  the 
pipe  may  get  clogged  with  dirt,  especially  if  the  soil  is  very 
fine. 

Drilled  wells.  On  the  whole  the  drilled  well  is  the  most 
satisfactory.  By  means  of  drills  and  machines,  a  hole  is 
drilled  in  the  ground  and  a  pipe  driven  down  the  hole  as 
fast  as  it  is  drilled.  Wells  of  this  type  may  be  drilled  to  a 
great  depth,  and  the  water  thus  obtained  is  pure,  if  care  is 
taken  that  the  pipes  do  not  leak. 

Springs.  Occasionally  springs  are  so  located  that  they 
may  furnish  a  satisfactory  source  of  water.  The  chief  con- 
sideration here,  as  with  dug  wells,  is  the  cleanliness  of  the 
surroundings.  If  there  is  no  source  of  impurity  near,  the 
spring  will  furnish  a  supply  of  good  water.  But  care  should 
be  taken  to  prevent  surface  pollution.  It  is  well  to  build  up  a 
casing  about  a  foot  above  the  ground  the  same  as  with  a  well. 


THE   HOME   WATER   SUPPLY 


49 


Brooks.  It  may  sometimes  happen  that  a  house  is  so 
situated  that  water  from  a  brook  may  be  piped  to  the  house. 
But  generally  such  sources  of  water  are  undesirable.  They 
are  open  to  many  sources  of  contamination  and  during  the 
summer  they  are  apt  to  dry  up  altogether. 

Cisterns.  Cisterns  are  sometimes  used  as  a  source  of 
drinking  water.  If  proper  precautions  are  taken,  these  may 
be  fairly  satisfactory.  The  cistern  should  be  water-tight 
to  prevent  impurities  from  entering.  Various  kinds  of 
impurities  gather  on  the  roof,  and  therefore  arrangements 
should  be  made  so  that  the  first  washings  from  the  roof 
during  a  rain  may  be  conducted  away,  and  then  the  later 
washings  turned  into  the  cistern. 

Pumps.  After  the  purity  of  the  water  is  assured,  the  next 
question  to  consider  is  the  method  by  which  the  water  is 
brought  into  the  house  and  distributed. 
One  of  the  most  common  methods,  espe- 
cially for  cisterns,  is  the  pump.  The 
ordinary  cistern  or  suction  pump  consists 
of  a  cylinder  C,  with  a  piston  P  that  works 
inside  the  cylinder.  This  piston  has  a 
leather  washer  so  that  it  fits  the  cylinder 
tightly.  In  the  center  of  the  piston  is  a 
weight  or  valve  V  so  arranged  that  pres- 
sure from  above  closes  it  tight,  while 
pressure  from  below  opens  it.  At  the  top 
of  the  pipe  jT,  where  the  pump  is  fastened, 
is  a  similar  valve  5  which  opens  up  and 
lets  the  water  through,  but  which  closes 
down  and  prevents  the  water  from  going 
back.  A  pipe  T  connects  the  cylinder 
with  the  well  or  cistern. 

How  the  pump  works.  In  order  to  understand  how  the 
pump  works,  let  us  suppose  that  the  cylinder  is  full  of  water 
and  that  the  pump  handle  is  down.  When  the  handle  is 


FIG.  15.  —  A  suction 
pump. 


50  SCIENCE  OF  HOME  AND   COMMUNITY 

lifted,  the  valve  V  in  the  piston  opens  and  the  water  passes 
through  while  the  piston  is  being  pushed  down  to  the  bottom 
of  the  cylinder.  When  the  handle  is  pressed  down,  the 
piston  P  is  lifted,  the  valve  V  in  the  piston  closes  and  the 
water  above  is  lifted  and  flows  out  through  the  spout.  At 
the  same  time  the  lower  valve  5  is  opened  upwards  and  the 
water  enters  and  fills  the  cylinder ;  and  then  the  operation 
is  repeated  as  before. 

It  is  easy  to  understand  how  the  piston  and  its  valve  works, 
but  what  causes  the  lower  valve  to  open  and  the  water  to 
rise  ?  To  push  water  up  in  this  way  requires  some  force  and 
we  are  curious  to  know  what  this  force  is.  It  is  the  weight 
of  the  air  pressing  down  on  the  surface  of  the  well  which 
forces  the  water  up  the  pipe. 

Weight  of  air.  Perhaps  you  do  not  realize  that  the  air 
has  weight,  but  it  has  been  proved  by  experiment.  By 
means  of  an  air  pump  the  air  has  been  pumped  out  of  air- 
tight vessels  and  the  vessel  weighed  before  and  after  removing 
the  air.  The  second  weight  is  found  to  be  less  than  the 
first,  the  difference  being  the  weight  of  the  air.  Air  is  very 
light  but  it  extends  up  so  high,  perhaps  twenty-five  to  fifty 
miles  or  more,  that  the  total  weight  of  air  bearing  down  on 
any  surface  is  very  great. 

Experiments  have  shown  that  the  air  bearing  down  on 
each  square  inch  of  surface  weighs  fifteen  pounds,  so  that  the 
air  bearing  down  on  your  hand  weighs  about  three  hundred 
pounds.  How,  then,  can  you  hold  your  arm  out  straight 
with  all  this  weight  on  it  ?  It  is  because  the  air  that  touches 
the  back  of  your  hand  pushes  up  with  the  same  force  that  the 
air  on  the  palm  of  your  hand  pushes  down,  so  that  the  two 
balance  and  you  do  not  feel  the  weight.  Likewise  the  air 
exerts  an  equal  pressure  side  wise,  thus  keeping  its  weight 
balanced  in  every  direction.  It  is  only  when  by  a  machine, 
such  as  an  air  pump,  the  air  is  removed  from  some  space, 
that  the  unbalanced  pressure  shows  its  tremendous  force. 


THE  HOME  WATER  SUPPLY  51 

The  weight  of  air  presses  down  on  the  water  in  the  cistern 
and  the  pressure  is  exerted  all  through  the  water,  so  that,  at 
the  opening  of  the  pipe,  water  is  forced  up  the  pipe  and  into 
the  cylinder  of  the  pump.  When  the  piston  of  the  pump  is 
raised,  a  vacuum  is  formed  in  the  cylinder  and  water  is 
forced  up  to  fill  this  space  by  the  weight  of  the  air  on  the 
surface  of  the  water  in  the  cistern. 

As  there  is  a  limit  to  the  weight  of  air,  so  there  is  a  limit 
to  the  height  to  which  water  may  be  pumped  by  the  com- 
mon suction  pump.  This  limit  is  the  height  of  a  column  of 
water  which  is  one  inch  square  and  weighs  fifteen  pounds. 
This  height  is  found  to  be  about  thirty-two  feet.  Air  will 
not  force  water  higher  than  this,  because  the  weight  of  this 
height  of  water  is  just  balanced  by  the  weight  of  air  extend- 
ing up  as  high  as  it  goes. 

DEMONSTRATION   n 

Purpose.     To  show  that  air  has  weight. 

Apparatus.  Air  pump,  bell  jar  with  open  top,  rubber  mem- 
brane. 

Directions.  Tie  a  piece  of  rubber  membrane  over  the  open 
top  of  a  bell  jar.  Place  the  bell  jar  on  t,Ve  tand  of  an  air  pump 
and  remove  the  air  by  means  of  the  puri/JF. 

LABORATORY  EXERCISE  7 

Purpose.  To  show  that  air  has  weight  and  hence  exerts  pres- 
sure. 

Apparatus.  Test  tube,  glass  tubing  about  six  inches  long, 
glass  tumbler,  piece  of  paper,  rubber  tubing  about  a  foot  and  a 
half  long,  pint  milk  bottle,  hard-boiled  egg  with  shell  removed. 

Directions,  i.  Fill  a  test  tube  with  water.  Place  your 
thumb  over  the  end  and  invert  it  in  a  dish  of  water.  Remove 
your  thumb  after  the  end  of  the  tube  is  under  water.  Why  does 
the  water  stay  in  the  tube  ? 

2.  Put  a  piece  of  glass  tubing  in  water  till  it  is  submerged. 
Place  your  finger  over  the  upper  end  and  remove  the  tube  from 


52  SCIENCE  OF  HOME  AND   COMMUNITY 

the  water.     Why  does  the  water  remain  in  the  tube  ?     Remove 
your  finger.     Why  does  the  water  fall  ? 

3.  Fill  a  tumbler  with  water.     Over  the  top  place  a  piece  of 
paper  and  press  it  down  firmly  on  the  rim.     Hold  the  paper 
on  with  one  hand  and  invert  the  tumbler  with  the  other.     Re- 
move the  hand  from  the  paper.     What  keeps  the  paper  up  ? 

4.  Submerge  a  piece  of  rubber  tubing  about  a  foot  and  a  half 
long  in  a  dish  of  water  till  the  tube  is  full  of  water.     Pinch  one 
end  of  the  tube  with  the  thumb  and  finger  and  bring  it  out  over 
the  edge  of  the  dish  into  another  empty  dish  placed  a  little  lower 
than  the  first.     Remove  the  hand.     What   makes  the  water 
flow?     Raise  the  second  dish  higher  than  the  first,  keeping  the 
end  of  the  tube  under  water  and  note  what  happens.     A  tube 
used  in  this  way  is  called  a  siphon. 

5.  Light  a  piece  of  paper  and  drop  it  into  a  pint  milk  bottle. 
After  the  flame  goes  out,  put  a  hard-boiled  egg  with  the  shell 
removed  in  the  mouth  of  the  bottle.     How  do  you  explain  what 
happens  ? 

6.  Do  these  experiments  help  you  to  explain  the  working  of 
a  fountain-pen  filler  and  why  it  is  possible  to  drink  soda  water 
by  means  of  a  straw  ? 

LABORATORY  EXERCISE  8 

Purpose.     To  shw-Jftow  a  pump  works. 

Apparatus.  A  small  cistern  pump  or  a  glass  model  of  a  lift 
pump. 

Directions.  Operate  the  pump  and  note  carefully  how  it 
works.  Take  it  apart  and  examine  the  various  parts.  Make 
a  drawing  of  the  pump  and  explain  how  each  part  works. 

Lift  pump.  If  the  well  is  deeper  than  thirty-two  feet,  a 
lift  pump  is  used.  In  this  kind  of  pump,  both  valves  are  in 
a  movable  cylinder,  which  may  be  placed  in  a  large  pipe, 
within  thirty-two  feet  of  the  surface  of  the  water.  The 
pressure  of  the  air  forces  the  water  up  to  the  cylinder,  and 
from  here  it  is  lifted  by  means  of  a  rod  attached  to  the 
cylinder  at  one  end  and  to  the  pump  handle  at  the  other. 


THE  HOME  WATER  SUPPLY 


53 


The  lower  part 


Frequently  the  cylinder  is  kept  below  the  surface  of  the 
water  in  the  well. 

Force  pump.  If  water  is  to  be  forced  higher  than  the 
spout  of  the  pump,  a  force  pump  is  used. 
5  and  T  is  like  the  ordinary  pump. 
The  spout  instead  of  being  open 
is  a  water-tight  pipe  which  con- 
nects with  an  air  dome  A .  As  the 
pump  is  worked,  water  is  forced 
into  this  dome  and  compresses 
the  air  there,  which  in  turn  forces 
the  water  out  through  another 
pipe,  giving  a  steady  flow  of 
water. 

Running  water  in  the  house. 
It  is  easier  and  less  expensive  than 
is  commonly  thought  to  have 
running  water  in  the  house,  and 
the  convenience  is  worth  the  ex- 
pense many  times  over. 

Gravity  system.  One  of  the  best 
systems  is  the  gravity  system, 
when  conditions  are  such  that  it  can  be  used.  For  this  pur- 
pose the  stream  or  spring  must  be  high  enough  above  the 
house  so  that  the  water  may  be  piped  directly  from  the 
source  of  water  supply  into  the  house.  This  system  is  cheap 
and  reliable,  but  the  necessary  conditions  are  found  only 
occasionally. 

fiydraulic  ram.  When  the  source  of  water  is  below  the 
level  of  the  house,  some  kind  of  pump  and  power  to  work  it 
must  be  used.  The  cheapest  method  is  the  hydraulic- ram, 
which  requires  a  running  brook  with  sufficient  fall  to  furnish 
the  needed  power,  and  a  very  liberal  supply  of  water,  as  the 
machine  wastes  about  seven  times  as  much  water  as  it 
pumps.  The  principle  involved  is  that  some  of  the  energy 


.  1 6.  — A  force  pump. 


54 


SCIENCE  OF  HOME  AND   COMMUNITY 


DISCHARGE 
PIPE    - 


of  the  running  water  is  used  to  compress  air  and  this  com- 
pressed air  forces  water  through  the  pipes.  The  ram  may 
pump  the  water  from  the  brook  that  operates  it,  or  it  may 
pump  water  from  a  separate  source.  The  advantages  are 
that  it  is  very  cheap  to  operate  and  requires  no  one  to  attend 
to  it.  Its  disadvantages  are  that  there  may  not  be  enough 
fall  of  water  or  stream  flow  to  operate  it,  and  that  the  accu- 
mulation of  air  in  the  summer  and  the  formation  of  ice  in 
the  winter  may  interfere  with  its  operation. 

Windmill.  Another  cheap  source  of  power  is  the  wind- 
mill. The  wheel  of  the  windmill  is  made  of  strong  blades 

of  wood  or  steel,  curved  or  flat, 
and  set  at  such  an  angle  that  the 
wind  blowing  against  them  causes 
the  wheel  to  rotate.  The  wheel 
must  be  kept  at  right  angles  to 
the  wind  in  order  to  be  turned  by 
it  and  it  is  kept  in  this  position 
by  a  fan-like  tail  which  works 
;°p  like  a  weathervane.  When  it  is 
desirable  to  stop  the  wheel,  this 
tail  can  be  turned  by  means  of  a 
wire  so  that  it  is  parallel  with  the  wheel,  which  then  turns  its 
edges  toward  the  wind  and  ceases  to  rotate.  On  the  axle 
is  a  cogwheel  that  fits  into  another  cogwheel  to  which  is  fas- 
tened a  crank.  This  moves  the  piston  of  the  pump  at  the 
base  of  the  windmill  up  and  down.  A  serious  objection  to 
the  windmill  is  that  the  time  of  its  operation  cannot  be  con- 
trolled. There  may  be  long  periods  of  calm,  and  a  large 
tank  must  be  provided  to  allow  for  this  possibility.  Water 
may  be  piped  directly  from  the  elevated  tank  to  the  house. 

An  objection  to  the  outdoor  tanks  in  the  northern  states, 
by  whatever  method  filled,  is  the  danger  of  freezing  during 
the  severest  weather.  Tanks  are  sometimes  placed  in  the 
attic  of  the  house,  but  there  is  always  the  danger  of  leakage 


FIG.  17.  —  Pneumatic 


THE  HOME  WATER  SUPPLY 


55 


or  that  the  weight  of  the  tank  when  full  may  prove  too  great 
a  strain  for  the  house. 

Pressure  tanks.     On  the  whole,  one  of  the  most  satisfactory 
devices  is  the  pressure  or  pneumatic  tank.     (See  figure  17.) 


FlG.  1 8.  —  Pneumatic  tank  system  of  water  supply  for  country  houses. 

This  is  an  iron  cylinder,  which  may  be  located  in  the  cellar  or 
sunk  in  the  ground  below  frost  line.     This  is  connected  with 


SCIENCE  OF  HOME  AND   COMMUNITY 


the  well  and  by  means  of  a  pump  the  water  is  pumped  into 
the  tank.  At  the  same  time  the  pump  compresses  the  air 
above  the  water  in  the  tank,  and  this  compressed  air  forces  the 
water  from  the  tank  up  through  the  pipes  leading  to  the  vari- 
ous parts  of  the  house.  Arrangements  are  made  to  pump  new 
air  into  the  tank  to  take  the  place  of  that  dissolved  by  the 
water.  The  pumping  may  be  done  by  hand,  by  windmills, 

by  gasoline  engines,  or 
by  electric  motors. 
Where  electricity  is 
available,  the  motor  is 
the  most  convenient, 
as  it  may  be  arranged 
to  work  automatically 
according  to  the  air 
pressure,  both  to  start 
and  to  stop. 

Hot-water  tank.  Run- 
ning water  in  the  house 
allows  of  a  constant 
supply  of  hot  water 
during  the  cold  weather 
when  the  fires  are  burn- 
ing. The  cold  water 
is  first  brought  into 
the  hot-water  tank  by 
means  of  a  pipe  extending  nearly  to  the  bottom  of  the  tank. 
The  water  is  heated  by  passing  through  coils  of  pipes  that 
are  placed  in  the  stove  or  furnace.  From  here  it  passes 
back  to  the  tank,  where  it  accumulates  in  the  upper  half 
and  is  drawn  off  from  the  top  and  circulates  through  the 
house. 


FIG.  19.  —  Hot-water  tank  and  water  front  in 
range. 


THE  HOME  WATER  SUPPLY  57 

HOME  PROJECT  7 

Purpose.  To  read  the  water  meter  and  compute  the  weekly 
cost  of  water. 

Directions,  i.  If  you  have  connections  in  your  home  with 
a  supply  of  running  water,  read  your  water  meter.  If  you 
have  the  straight  reading  register,  copy  the  figures  found  there. 
If  you  have  a  dial-reading  register,  make  a  drawing  in  your 
notebook  of  your  meter.  Draw  each  circle,  copying  the  figures, 
and  draw  in  the  pointer  in  its  proper  place  with  reference  to  the 
figures.  Bring  the  drawing  to  school  so  that  the  teacher  may 
explain  how  to  read  the  meter. 

2.  One  week  later,  make  another  reading  and  subtract  the 
first  reading  from  the  second.  Find  the  price  charged  for  water 
and  estimate  the  cost  of  one  week's  supply. 


SUPPLEMENTARY   QUESTIONS  FOR   CLASS  DISCUSSION 

1 .  Which  is  the  best  type  of  well  ? 

2.  How  do  the  lift  pump  and  force  pump  differ  from  the 
cistern  pump  ? 

3.  What  are  the  advantages  of  having  running  water  in  the 
house  ? 

4.  Of  how  many  facts  can  you  think  which  show  that  air 
has  weight? 

REFERENCES 

Bashore,  Outlines  of  Rural  Hygiene,  F.  A.  Davis  Co.,  New  York 

City.     Chap.  i. 
Lynde,    Home   Water   Works,  Sturgis  and  Walton,   New  York 

City. 
Harper's  Machinery  Book  for  Boys,  Harper  Bros.,  New  York 

City.     Chap.  6  (Windmill). 


CHAPTER  V 
THE   HYGIENE   OF  THE   DINING  ROOM 

How  may  we  know  what  kinds  of  food  we 
should  eat  and  how  much  in  order  to  keep  our 
bodies  in  the  best  health  ? 

In  considering  the  matter  of  foods,  two  questions  arise: 
first,  what  kind  of  foods  should  be  eaten,  and  second,  how 
much  food  should  be  eaten.  The  first  question  may  be 
looked  at  from  two  standpoints,  from  that  of  health  and 
from  that  of  cost. 

Uses  of  foods.  In  order  to  answer  these  questions,  we 
must  first  understand  the  uses  of  foods  in  the  body.  Foods 
serve  three  purposes :  first,  they  furnish  material  for  the 
growth  and  repair  of  the  parts  of  the  body;  second,  they 
supply  the  body  with  fuel,  which  yields  heat  to  keep  the 
body  warm  and  furnishes  power  by  which  the  muscles  work ; 
third,  they  regulate  some  of  the  processes  of  the  body,  such 
as  the  beating  of  the  heart,  the  digestion  of  food,  and  other 
activities  that  are  constantly  taking  place  in  the  body.  The 
body  may  be  likened  to  a  furnace.  As  the  fuel  is  burned  in 
the  furnace  and  furnishes  heat  and  energy,  so  food  is  used 
for  maintaining  life  in  the  body.  There  is  nothing,  however, 
in  the  work  of  the  furnace  which  corresponds  to  the  first 
use  of  foods,  for  the  furnace  cannot  build  and  repair  its  parts 
as  the  body  can. 

Kinds  of  nutrients.  Studies  that  have  been  made  of  foods 
show  that  while  we  have  a  great  variety  of  foods,  yet  the 
kinds  of  substances  in  them  that  actually  nourish  the  body 
may  be  divided  into  a  few  groups  of  nutrients.  The  five 

58 


THE  HYGIENE  OF  THE  DINING  ROOM 


59 


kinds  of  nutrients  are  proteins,  fats,  carbohydrates,  water, 
and  mineral  matters.  All  of  our  foods  contain  one  or  more 
of  these  nutrients.  In  selecting  foods  we  are  concerned 
chiefly  with  the  first  three  nutrients.  Examples  of  pro- 
tein are  white  of  eggs,  the  lean  part  of  meats,  and  the  gluten 
of  flour ;  examples  of  carbohydrates  are  sugar  and  starch, 
such  as  is,  found  in  vegetable  foods;  examples  of  fats  are 
butter  and  the  fatty  portions  of  meats. 

LABORATORY  EXERCISE  9 

Purpose.     To  test  foods  for  different  kinds  of  nutrients. 

Materials.  Various  kinds  of  foods,  iodin,  nitric  acid, 
ammonia. 

Directions,  i.  To  test  for  starch.  Heat  a  little  corn  starch 
in  water  and  allow  it  to  cool.  Then  add  a  few  drops  of  a  dilute 
solution  of  iodin  in  alcohol.  A  blue  color  shows  the  presence 
of  starch.  In  a  similar  way  test  a  number  of  common  foods. 

2.  To  test  for  proteins.     Add  a  little  nitric  acid  to  a  piece 
of  meat  in  a  test  tube  and  boil.     Pour  out  the  acid,  rinse  the 
meat  in  water,  and  add  ammonia.     The  yellow  color  is  a  test 
for  proteins.     Test  a  number  of  foods  for  proteins. 

3.  To  test  for  fats.     Place  a  piece  of  butter  on  a  sheet  of 
writing  paper  and  warm  over  a  flame  till  it  melts.     Then  rub 
off  the  butter  and  notice  the  change  that  has  taken  place  in 
the  paper.     This  effect  in  making  the  paper  transparent  is  a 
test  for  fat.     Test  other  foods  for  fat. 

4.  Put  records  in  the  form  of  the  following  table. 


KIND  OF  FOOD 

STARCH 

PROTEIK 

FAT 

Put  the  names  of  the  foods  in  the  first  column  and  put  a 
check  opposite  each  food  in  the  proper  column  to  correspond 
with  the  tests. 


60  SCIENCE  OF  HOME  AND   COMMUNITY 

Uses  of  nutrients.  The  only  kind  of  nutrient  which  can 
build  tissue  is  protein,  hence  a  certain  amount  of  this 
kind  of  food  is  absolutely  necessary  for  the  maintenance  of 
the  body ;  but  the  amount  needed  is  less  than  was  formerly 
considered  necessary.  Proteins  also  serve  as  fuel  in  the 
body,  but  it  is  better  that  most  of  this  fuel  be  obtained  from 
other  foods.  Carbohydrates  and  fats  cannot  build  tissues, 
but  they  serve  the  purpose  of  foods  in  yielding  fuel  to  keep 
the  body  warm  and  to  furnish  energy  for  the  muscles. 
Mineral  matters  aid  in  forming  bone  and  other  tissues  and 
help  to  regulate  some  of  the  activities  of  the  body.  Water 
supplies  the  body  tissues  with  fluid  and  carries  nutrients  in 
solution. 

Vitamines.  Recent  studies  of  foods  have  shown  that  in 
addition  to  the  five  nutrients  mentioned  above  there  are 
other  substances,  called  vitamines,  that  are  important  for 
a  proper  diet.  These  substances  serve  a  very  important 
purpose  in  regulating  some  essential  body  processes,  such 
as  the  contraction  of  the  muscles  and  the  absorption  of 
food  from  the  intestines.  When  these  vitamines  are  lack- 
ing in  the  diet  serious  results  to  health  follow.  It  is  known 
that  there  are  two  classes  of  these  substances,  one  of  which 
is  soluble  in  water  and  the  other  in  fat.  The  one  soluble  in 
water  is  found  in  many  foods,  including  milk,  eggs,  meat, 
the  bran  and  germ  of  cereals,  succulent  vegetables,  legumes, 
and  probably  in  all  fruits.  The  one  soluble  in  fat  is  found 
less  widely  distributed  and  more  care  is  necessary  in  plan- 
ning the  diet  to  see  that  it  is  included.  This  is  found  in 
green  leaves,  such  as  lettuce,  in  eggs,  liver,  and  the  fat  of 
milk.  It  is  found  to  a  lesser  extent  in  meats,  especially  in 
the  organs  of  the  body  and  the  fat  near  them. 

Digestion  of  food.     Before  the  nutrients  can  be  used  in 

the  body  they  must  go  through  the  process  of  digestion, 

•  the  purpose  of  which  is  to  change  foods  into  a  soluble  form 

so  that  they  can  be  absorbed  into  the  blood  and  used  by 


THE   HYGIENE   OF  THE  DINING  ROOM 


6l 


U.  S.  Department  of  Agriculture 
Office  of  Experiment  Stations 
A.  C.  True:  Director 


Prepared  by 

C.  F.  LANGWORTHY 

Expert  in  Charge  of  Nutrition  Investigations 


COMPOSITION  OF  FOOD  MATERIALS. 


mm 

Protein  Fat         Carbohydrates 

LAMB  CHOP 

EDIBLE  PORTJON 

•  Water  :53.1 


Ash 


•     Fuel  Value 
^Sq.ln.Equals 
1000  Calories 

PORK  CHOP 

EDIBLE  PORTION 

Water:  52. 


ak.28.3 


Prate 


Fat:30.1 


Ash:1.0 
FUEL  VALUE: 


1540  CALORIES 
PER  POUND 


BEEF  STEAK 

EDIBLE  PORTION 

Water:  61 .9 


SMOKEX)  HAM 

EDIBLE  PORTION 


Water:  40. 
Protein:16.1 


Fat:  38.8 


Ash:1.0 


1580  CALORIES 
PER  POUND 


Ash:4.8 


FUEL 

VALUE: 


1.940  CALORIES 
PER  POUND 


DRIED  BEEF 

EDIBLE  PORTION 

Protein: 
30.0 


Fat:18.5 


FUEL 

VALUE: 


1  1  30  CALORIES 
PER  POUND 


FUEL 

VALUE:! 


Ash:9.1 

1840  CALORIES 
PER  POUND 


FIG.  20.  —  Composition  of  meats. 


62  SCIENCE  OF  HOME  AND   COMMUNITY 

the  body.  The  process  of  digestion  begins  in  the  mouth, 
where  the  saliva  acts  on  the  starches,  changing  them  into 
sugars.  In  the  stomach  the  gastric  juice  acts  on  the  pro- 
tein, changing  it  to  a  soluble  form  known  as  peptone.  The 
food  is  thoroughly  worked  over  here  and  reduced  to  a  fine 
semi-liquid  state  before  it  passes  on  to  the  small  intestines. 
Just  after  the  food  leaves  the  stomach  it  comes  in  contact 
in  the  small  intestines  with  the  pancreatic  juice,  which  has 
the  power  of  digesting  all  three  kinds  of  nutrients.  It 
finishes  the  work  begun  by  the  saliva  in  digesting  the  starches, 
and  that  begun  by  the  stomach  in  digesting  the  proteins, 
and  in  addition,  with  the  aid  of  bile,  it  digests  the  fats. 

Absorption  of  foods.  After  the  foods  are  digested,  they 
are  absorbed  through  the  walls  of  the  intestines  and  carried 
by  the  blood  to  the  various  parts  of  the  body,  where  they 
are  used.  The  waste  products  resulting  from  the  oxidation 
of  foods  are  given  off  by  the  various  excretory  organs  of  the 
body.  The  carbon  dioxid  and  some  of  the  water  resulting 
from  the  burning  of  the  food  pass  off  through  the  lungs. 

Exercise  and  digestion.  The  subjects  of  exercise  and 
digestion  are  closely  related.  One  of  the  chief  values  re- 
sulting from  exercise  lies  in  the  beneficial  results  which  it 
has  on  the  process  of  digestion.  It  is  a  well-known  fact  that 
those  people  who  are  doing  heavy  muscular  work  are  less 
afflicted  with  digestive  troubles  than  those  who  secure  little 
muscular  exercise.  People  who  change  their  occupations 
or  habits  to  those  which  require  less  muscular  effort  often 
find  that  their  general  health  is  much  poorer.  It  is  specially 
important  for  those  living  a  sedentary  life  that  some  form  of 
exercise  should  be  taken  regularly  to  insure  the  proper  work- 
ing of  the  digestive  system  as  well  as  of  the  other  systems  of 
the  body. 

Our  first  answer  to  the  question  as  to  what  kinds  of  food 
we  need  is  that  we  must  have  foods  which  furnish  enough 
of  the  proteins  to  build  up  and  repair  our  body  tissues  and 


THE  HYGIENE  OF  THE  DINING  ROOM 


enough  of  the  fats  and  carbohydrates  to  keep  our  bodies 
warm  and  to  furnish  energy  for  the  muscles.  So  we  next 
inquire  from  what  foods  we  can  best  secure  these  proteins, 
fats,  and  carbohydrates. 

Sources  of  proteins.     Protein  is  an  important  constituent 
of  meats,  fish,  beans,  peas,  cereals,  and  nuts.     (See  figure  21.) 


FIG.  21.  —  Protein  foods. 

It  comprises  about  one  tenth  of  cereals  (see  figure  28),  one 
seventh  of  meats  (see  figure  20),  one  fifth  of  dried  beans  and 
peas,  and  one  fourth  of  cheese.  (See  figure  26.)  Nuts 
vary  greatly  in  composition,  peanuts  containing  about  one 
twelfth.  Fruits  and  vegetables  contain  only  small  quanti- 
ties of  protein.  (See  figure  25.) 

Source  of  fats  and  carbohydrates.  The  chief  sources  of 
fats  are  nuts  and  the  animal  foods.  (See  figure  22.)  The 
carbohydrates  are 
obtained  almost  en- 
tirely from  vegeta- 
ble foods  (see  figure 
23),  milk  and  liver 
being  the  only  ani- 
mal foods  that  con- 
tain any  appreciable 
quantity.  The  car- 
bohydrates make  up  about  two  thirds  of  peas  and  beans, 
three  fourths  of  the  cereals  (see  figure  28),  and  a  large 
proportion  of  the  nutrients  of  vegetables  and  fruits.  It  is 
thus  seen  that  animal  foods  contain  large  proportions  of 


FIG.  22.  —  Fat  foods. 


64  SCIENCE  OF  HOME  AND   COMMUNITY 

protein  and  fat  with  small  proportions  of  carbohydrates, 
while  vegetable  foods,  excepting  nuts,  contain  large  pro- 
portions of  carbohydrates,  but  little  fat,  and  some  contain 
large  proportions  of  protein. 

Water.  Water  forms  a  large  proportion  of  nearly  all 
foods.  The  amount  varies  greatly.  Vegetables  and  fruits 
contain  the  largest  proportion,  ranging  from  eighty  to  ninety- 
five  per  cent.  (See  figure  25.)  Nuts  and  dried  foods,  like 
peas,  beans,  wheat,  and'  corn  contain  the  smallest  propor- 
tion, ranging  from  five  to  fifteen  per  cent.  (See  figure  28.) 
Meats  contain  a  medium  amount,  ranging  from  fifty  to 
seventy  per  cent.  (See  figure  20.) 

Mixed  diet.  In  selecting  food  to  furnish  the  protein 
which  we  must  have,  we  may  choose  from  meats,  fish,  beans, 
peas,  cereals,  and  nuts.  The  carbohydrates  we  get  almost 
entirely  from  vegetable  foods,  and  the  fats  largely  from 
animal  foods,  and  to  a  minor  extent  from  nuts.  It  will  be 
seen  from  this  that  it  is  possible  to  obtain  all  the  nutrients 
that  the  body  needs  from  vegetable  foods  alone.  There  are 
some  people,  called  vegetarians,  who  maintain  that  this  is  a 
more  healthful  diet  than  one  composed  of  both  animal  and 
vegetable  foods.  The  agitation  aroused  by  these  people  has 
undoubtedly  had  beneficial  results  in  showing  that  people 
generally  use  more  animal  food  than  the  body  requires  and 
that  a  diet  with  a  larger  proportion  of  vegetable  food  and  a 
smaller  proportion  of  animal  food  would  be  more  healthful. 
But  the  consensus  of  common  experience  and  of  medical  ad- 
vice is  that  for  most  people  a  mixed  diet  is  preferable  to  a 
vegetarian  diet.  A  mixed  diet  allows  a  greater  variety  of 
foods  and  makes  it  easier  to  select  foods  containing  the 
proper  proportions  of  nutrients.  (See  figure  24.) 

Fruits  and  vegetables.  (See  figure  25.)  In  the  foregoing 
discussion  little  mention  has  been  made  of  fruits  and  vege- 
tables. While  these  do  not  contain  large  proportions  of  solid 
nutrients  and  are  not  among  the  cheaper  foods,  they  are 


THE  HYGIENE   OF  THE  DINING  ROOM  65 

among  the  best  foods  and  should  occupy  a  place  in  every 
diet.  They  are  composed  largely  of  water.  Of  the  nutrients 
present,  carbohydrates  are  the  most  common.  These  carbo- 
hydrates help  to  furnish  a  well-balanced  diet  when  used  in 


FIG.  23.  —  Carbohydrate  foods. 

connection  with  the~protein  foods.  But  in  addition  to  their 
direct  food  value,  they  serve  other  important  uses.  The 
pleasant  flavors  of  fruits  and  vegetables  serve  to  make  other 
foods  more  palatable  and  so  aid  in  their  digestion.  They 
furnish  also  some  of  the  mineral  salts  needed  by  the  body, 
and,  by  the  bulk  of  material  which  they  contain,  they  assist 
in  the  proper  working  of  the  digestive  organs.  Fruits  and 
vegetables  are  valuable  also  because  they  contain  small 
quantities  of  substances  called  vitamines,  which  are  essential 
to  the  well-being  of  the  body.  Cooking  either  diminishes  or 


FIG.  24.  —  Food  elements  in  a  sandwich. 

destroys  these  vitamines,  and  some  uncooked  fruits  and  veg- 
etables should  be  eaten. 

Fruits  and  vegetables  can  be  easily  raised  in  the  home 
garden 'at  slight  expense  and  with  but  little  labor.  This  is 
especially  true  of  vegetables  which  can  be  raised  from  seed 
in  one  season.  The  fruits,  excepting  fall  strawberries,  re- 
quire longer  to  mature,  varying  from  two  to  ten  years. 
Vegetables  have  good  keeping  qualities,  and,  of  the  surplus 


66  SCIENCE  OF  HOME  AND   COMMUNITY 

raised  in  the  summer,  many  kinds  may  be  stored  or  canned 
for  winter  use. 

Nuts.  Another  kind  of  food  of  which  mention  should 
be  made  is  nuts.  The  value  of  these  and  the  place  they 
should  occupy  in  our  diet  has  been  largely  misunderstood. 
As  regards  their  composition,  nuts  are  among  the  most 
concentrated  foods  we  have,  the  edible  portions  containing 
only  a  small  per  cent  of  water  (five  to  seven  per  cent) .  The 
important  characteristic  of  nuts  as  food  is  the  large  propor- 
tion of  protein  and  fat  which  they  contain ;  they  rank  with 
meats  and  cereals  in  the  proportion  of  protein  and  greatly 
exceed  the  meats  in  the  amount  of  fats. 

Mistakes  in  the  use  of  nuts  as  food  have  arisen  from  failure 
to  understand  these  two  facts ;  first,  that  nuts  contain  large 
amounts  of  protein,  and  second,  that  they  are  very  concen- 
trated. Their  proper  place  is  as  a  substitute  for  other 
"protein  foods  such  as  meats  and  beans,  and  not  as  an  addition 
to  a  hearty  meal.  Nuts  have  had  the  reputation  of  being 
indigestible,  but  this  has  resulted  largely  from  the  way  in 
which  they  have  been  used.  They  should  not  be  eaten  at 
the  end  of  a  hearty  meal  when  sufficient  protein  food  has 
already  been  eaten.  It  is  much  the  same  as  though  a  course 
of  meat  should  be  served  at  the  end  of  a  hearty  dinner. 

One  precaution  should  be  noted  in  eating  nuts :  they 
should  be  thoroughly  masticated,  because  they  are  such 
concentrated  foods.  Failure  to  do  this  has  undoubtedly 
been  another  cause  of  the  ill  effects  felt  after  eating  nuts. 
When  they  occupy  the  proper  place  in  our  diet  and  are 
thoroughly  masticated,  nuts  may  form  an  important  and 
healthful  article  of  food.  Those  people  who  prefer  a  vegeta- 
ble diet  may  make  nuts  one  of  their  chief  sources  of  protein. 

Special  mention  should  be  made  of  peanuts  on  account 
of  their  cheapness.  Nuts  as  a  class  are  a  rather  expensive 
food,  but  peanuts  as  a  source  of  both  protein  and  energy 
are  much  cheaper  than  meats  and  of  equal  value  with  cereals 


THE  HYGIENE  OF  THE  DINING  ROOM 


67 


U.  S.  Bepartment  of  Agriculture  Prepared  by 

Office  of  Experiment  Stations  C.  F.  LANGWORTHY 

A.  C.  True:  Director  Expert  in  Charge  of  Nutrition  Investigations 

COMPOSITION  OF  FOOD  MATERIALS. 

Fuel  Value 
Sq. In. Equals 
1000  Calories 


Dnnn 

Protein  Fat         Carbohydrates 


Ash 


Water 


FUEL     VALUE: 


I 


230  CALORIES 
PER  POUND 


ONION 


Carbohydrates:  9.9 


/^Water:83.0 

Protein:!. 6 
Fat:0,5 
Carbohydrates;  13.5 

h:L4 


FUEL    VALUE: 

225   CALORIES 
PER  POUND 


PARSNIP 

POTATO 

Protein:2.2 


Carbohydrates:  18.4     ^*Water:78.3 

FUEL   VALUE:  ProteinLLLJ 

Carbohydrates:  3 


I 


385   CALORIES  PER  POUND 


Water:94.5 


Ash:1.0 


FIG.  25.  —  Composition  of  vegetables. 


68 


SCIENCE  OF  HOME  AND   COMMUNITY 


U.  S.  Department  of  Agriculture  Prepared  by 

Office  of  Experiment  Stations  C.  F.  LANGWORTHY 

A.  C.  True:  Director  Expert  in  Charge  of  Nutrition  Investigations 

COMPOSITION  OF  FOOD  MATERIALS. 

FuelVaJue 
Protein  Fat         Carbohydrate*         Ash  Water 

WHOLE  EGG 


FUEL  VALUE  OF 

WHOLE  EGG: 


700  CALORIES 
PER  POUND 


CREAM  CHEESE 

Water:  34.: 


FUEL    VALUE    OF  YOLK: 


1 608      CALORIES 
PER  POUND 


Protein  :1 3.0 

Fat:  0.2 
Ash:0.6 

FUEL    VALUE    OF  WHITE: 


1 


265   CALORIES 
PER  POUND 


COTTAGE  CHEESE 


.tein:  25.9  Water:  72.0 


Carbo- 
ydrates:  2.4 


in:  20.9 


Carbo- 


hydrates: 4. 3 


FUEL  VAIUE: 


1950    CALORIES  PER  POUID 


510    CALORIES  PER  POUND 


FIG.  26.  —  Composition  of  eggs  and  cheese. 


THE  HYGIENE  OF  THE  DINING  ROOM 


69 


in  this  respect.  The  edible  portion  contains  a  larger  per 
cent  of  protein  and  fats  than  meats  and  cereals  contain. 

Milk.  Milk  is  one  of  the  very  best  of  all  our  foods.  For 
children  it  is  almost  a  necessity.  It  is  well-balanced  in  the 
proportions  of  nutrients  that  it  contains  as  is  shown  in  the 
table  given  below.  Milk  serves  all  three  purposes  of  foods. 
It  furnishes  energy  at  a  moderate  price  in  comparison  with 
other  foods  ;  it  is  a  cheap  source  of  protein  ;  and  it  is  one  of 
the  most  important  sources  of  those  substances  called 
vitamines,  which  are  so  essential  in  regulating  the  body 
activities.  It  is  the  richest  of  all  the  common  foods  in  lime, 
a  substance  necessary  to  build  bones. 

In  these  times  when  so  much  stress  is  being  laid  on  the 
economical  use  of  foods,  special  attention  is  called  to  the  fact 
that  skimmed  milk  is  almost  as  good  a  food  as  whole  milk. 
Reference  to  the  table  given  below  shows  that  the  chief 
difference  is  that  the  skimmed  milk  contains  less  fat,  but  the 
proportions  of  the  other  nutrients  are  the  same.  Skimmed 
milk  is  sold  at  such  a  low  price  that  it  is  one  of  the  cheapest 
foods. 


WATER 

PROTEIN 

FAT 

CARBOHYDRATES 

Whole  Milk  .... 
Skimmed  Milk  .     .     . 

87% 
9^-5% 

3-3% 

34% 

4& 

5% 
5-i% 

LABORATORY  EXERCISE  10 

Purpose.  To  compare  foods  as  regards  their  nutritive 
value. 

Directions.  Answer  the  following  questions  from  the  study 
of  the  table  given  on  page  71. 

i.  Which  foods  contain  the  larger  per  cent  of  proteins, 
animal  or  vegetable  foods?  Which  of  carbohydrates?  Which 
of  fats  ? 


70  SCIENCE  OF  HOME  AND   COMMUNITY 

2.  Among  the  animal  foods,  which  three  contain  the  largest 
per  cent  of  protein  ?     Which  one  the  least  ? 

3.  Among  the   vegetable  foods,  which   three   contain  the 
largest  per  cent  of  protein  ?     Which  two  the  least  ? 

4.  Which  two  foods  contain  the  largest  per  cent  of  carbo- 
hydrates ?     Which  one  the  least  ? 

5.  Which  four  foods  contain  the  largest  per  cent  of  fats? 
Which  three  contain  the  least?     Which  four  have  the  largest 
fuel  value  ? 

6.  Which    kind    of    nutrient    do    we    get    almost    wholly 
from  vegetable  foods  alone?     Which  kind  chiefly  from  animal 
foods   alone?     Which  kind  from  both   animal   and  vegetable 
foods  ? 

7.  Which  five  kinds  of  foods  contain  the  largest  per  cent 
of  proteins  arranged  in  order?     Which  five  of  fats?     Which 
five  of  carbohydrates  ?    (See  10  below.) 

8.  Which  five  foods  have  the  most  refuse?     Which  have 
none? 

9.  Which  five  have  the  largest  per  cent  of  water?     Which 
five  the  least  ? 

10.  Put  your  answers  giving  foods  with  the  largest  per  cents 
of  the  various  nutrients  in  the  following  tabular  form.  Under 
each  heading  put  the  five  foods  that  come  first,  arranged  in 
order. 


PROTEIN 

FAT 

CARBOHYDRATES 

WATER 

REFUSE 

FUEL  VALUE 

1 1 .  The  members  of  the  class  may  cooperate  to  make  colored 
charts  showing  the  composition  of  foods.  Secure  six  large  pieces 
of  heavy  paper.  Copy  on  these  pieces  the  outlines  of  the  foods  in 
figures  20,  25,  26,  27,  28,  and  30,  on  an  enlarged  scale.  Indicate 
the  proportions  of  the  nutrients  by  different  colors,  using  either 
water  colors  or  colored  crayons. 


THE  HYGIENE  OF  THE  DINING  ROOM 


TABLE  SHOWING  COMPOSITION  OF  FOODS  AS  PURCHASED 


p 

ER  CENT  o 

F 

FUEL  VALUE 

Protein 

Fat 

Carbo- 
hydrates 

Water 

Refuse 

PER  POUND 
CALORIES 

Animal  Foods 

Cheese   

20 

^6 

- 

•22 

o 

2Qcc 

Fowl       

X 

14 

12 

0 

o 

47 

26 

765 

Halibut       .... 

J  I- 

A 

o 

62 

18 

AJ7S. 

Lobsters     .... 

6 

T 

•7 

.2 

62 

t/  O 

145 

EP'PS 

i  "^ 

o 

66 

ii 

61  ^ 

Milk  

T.   T. 

A 

87 

o 

_ 

Pork  chops 

o  o 
13 

*r 

24 

0 

/ 

42 

20 

1245 

Lamb  (leg)      .     .     . 

16 

20 

0 

50 

14 

1130 

Round  steak   . 

19 

13 

o 

61 

7 

890 

Sirloin  steak    .     .     . 

17 

16 

0 

54 

13 

975 

Vegetable  Foods 

Apples    . 

A 

M 

II 

61 

2C 

IQO 

ii.F.t-»iv~ 

Beans  (dried)  . 

23 

2 

60 

"O 

13 

0 

j.  v/vy 

1520 

Beets                .     . 

I 

.1 

8 

7O 

2O 

1  60 

Corn  meal  .... 

9.2 

2 

75 

/  w 
13 

0 

1655 

Grapes 

I 

I 

id 

-0 

2^ 

.,  ,,  ,. 

Lettuce       .     .     .     . 

I 

.2 

T- 
3 

81 

15 

65 

Oranges      .... 

.6 

.1 

9 

63 

27 

150 

Peanuts      .... 

20 

29 

19 

7 

25 

1775 

Potatoes     .... 

2 

.1 

15 

67 

20 

295 

Strawberries    .     .     . 

•9 

.6 

7 

90 

5 

180 

Wheat  flour     .     .     . 

ii 

i 

75 

12 

0 

1635 

Cost  of  foods.  Now  that  we  have  determined  what  foods 
contain  the  nutrients  the  body  needs,  the  next  problem  is 
to  ascertain  what  foods  give  the  largest  amount  of  nutrients 
for  the  least  cost.  This  cannot  always  be  determined  by 
comparing  the  price  per  pound  or  quart,  for  we  must  know 
also  the  proportions  of  nutrients  that  the  foods  contain. 

People  are  often  misled  by  the  idea  that  the  higher  the 
price  paid,  the  better  the  food.  This  idea  is  entirely  wrong 
as  applied  to  foods.  The  price  of  foods  is  not  determined 
by  the  nutrients  they  contain,  but  largely  by  other  factors 


72 


SCIENCE  OF  HOME  AND   COMMUNITY 


U.S.  Department  of  Agriculture 

Office  of  Experiment  Stations 

A.C.  True:  Director 


Prepared  by 

C.F.  LANGWORTHY 

Expert  in  Charge  of  Nutrition  Investigations 


COMPOSITION  OF  FOOD  MATERIALS. 


Protein 

COD 

Lean  Fish 


Fat 


Carbohydrates 


Ash 


FUEL     VALUE: 

Water:82.6  I 


325  CALORIES 
PER  POUND 
Protein,:  15. 8 


Water 


FUEL    VALUE 

Water 

410    CALORIES 
PER    POUND 

Protein 


•     Fuel  Value 
Ks  Sq. In. Equals 
1000  Calorie 

SALT  COD 


OYSTER 

Water:86.9 


Ash:24.7 


Carbohydrates:-3.. 
SMOKED  HERRING 


ater.34.6 
Protein:36.4 

FUEL    VALUEI 


1355   CALORIES 
PER  POUND 


MACKEREL 

Fat  Fish 


Ash:13.2\ 


235    CALORIES 
PER    POUND 


FUEL     V.ALUE: 

n 

645    CALORIES 
PER    POUND 


FIG.  27.  —  Composition  of  fish. 


THE  HYGIENE  OF  THE  DINING  ROOM*  73 

such  as  rarity,  appearance,  tenderness,  flavor,  or  cost  of 
production,  factors  which  influence  only  slightly  the  real  value 
of  foods.  For  illustration,  take  the  case  of  sirloin  and 
round  steaks.  Sirloin  costs  more,  chiefly  because  it  is  more 
tender,  and  yet  it  contains  more  waste  and  less  protein ;  and 
hence  it  is  really  not  so  valuable  a  food  as  round  steak. 

If  we  compare  fresh  codfish  with  oysters,  we  find  a  much 
higher  price  is  charged  for  oysters  largely  on  account  of  the 
flavor  and  rarity ;  yet  if  the  same  amount  of  money  be  in- 
vested in  both,  twice  as  much  food  material  and  three  times 
as  much  protein  will  be  obtained  in  the  codfish  as  in  the 
oysters. 

A  man  who  made  a  careful  study  of  portions  of  food  served 
in  restaurants  in  New  York  City  found  that  five  cents  in- 
vested in  a  roast -beef  sandwich  bought  358  calories,  while 
five  cents  invested  in  raw  oysters  bought  only  19  calories. 
That  is,  the  sandwich  furnished  18  times  as  many  calories  as 
the  oysters,  and  yet  they  both  cost  the  same. 

The  following  table  shows  the  difference  in  cost  of  100 
calories  for  various  kinds  of  foods  : 

COST  OF  100  CALORIES 

Corn  meal  (6  cts.  Ib.) f  cent 

Dried  beans  (locts.  Ib.) f  cent 

Milk  (IT  cts.  qt)  . if  cents 

Cheese  (;o  cts.  Ib.) 2  cents 

Almonds  (35  cts.  Ib.) 3^  cents 

This  table  shows  that  for  any  given  sum  of  money  one 
can  get  nine  times  as  many  calories  from  corn  meal  as  from 
almonds. 

The  foods  which  furnish  protein,  arranged  in  order  of 
cost  beginning  with  the  cheapest  are :  dried  beans,  cereals, 
peanuts,  meats,  fish.  From  the  standpoint  of  the  second 
purpose  of  foods,  that  is  to  furnish  the  body  with  fuel,  the 


74 


SCIENCE  OF  HOME  AND    COMMUNITY 


U.  S.  Department  of  Agriculture 

Office  of  Experiment  Stations 

A.  C.  True:  Director 


Prepared  by 
C.  F.  LANGWORTHY 
Expert  in  Charge  of  Nutrition  Investigations 

COMPOSITION  OF  FOOD  MATERIALS. 


Lto  Sq. In. Equals 
1  1000  Calories 


Protein  Fat          Carbohydrates         Ash 

CORN 


Water 


WHEAT 


Fat.4.3 


•Water:10.8 
Protein:  10.0 


Water:10.6 


AsrrJ  5.J3lil^arkohy^rates:73'4  Carbohydrates. §73.7 


FUEL  VALUE: 


BUCKWHEAT 


at:  1.7 


Ash:  1 .8 


1800  CALORIES       Proteln:10.0^ggrWateT:12.6      1750  CALOR1ES 


PER  POUND          Carbc 

hydrates:73.2"***^-Ash:  2.0 

FfcEL    VALUE: 


PER  POUND 


OAT 


RICE 


•^••••^•l 

-Water:  11.0         1600  CALORIES      Water:12.0- 
-Proteln:l1.8        PER  POUND    Protein: 


—  Ashrl.O 


hydrates:73.9  \igU-Ash:  1.9 

1720  CALORIES  FUEL  VALUE: 

PER  POUND 

1750  CALORIES 
PER  POUND 


1  720  CALORIES 
PER  POUND 


FIG.  28.  —  Composition  of  cereals. 


THE   HYGIENE   OF  THE   DINING  ROOM  75 

foods  arranged  in  order  of  cheapness  are  :  cereals,  dried  beans, 
potatoes,  peanuts.  It  is  thus  seen  that  cereals  and  dried 
beans  are  the  cheapest  foods  from  both  standpoints. 


LABORATORY  EXERCISE  n 

Purpose.  To  find  out  which  are  the  cheapest  foods  and 
which  are  the  most  expensive. 

Directions,  i.  Find  the  price  per  pound  of  the  various 
foods  given  in  the  table  on  page  71.  If  some,  like  oranges,  are 
sold  by  the  dozen,  weigh  a  few  and  from  this  compute  the  price 
per  pound. 

2.  From  these  figures  showing  the  price  per  pound,  compute 
for  each  food :   (a)  the  cost  of  a  pound  of  protein ;   (6)  the  cost 
of  1000  calories  fuel  value.     For  example,  if  the  price  of  round 
steak  were  25  cents,  divide  25  cents  by  .19  the  per  cent  of  pro- 
tein.    This  gives  $1.31  the  cost  of  a  pound  of  protein.     To  find 
the  cost  of   1000  calories,  divide  the  figure  given  in  the  last 
column  by  1000  and  then  divide  the  price  per  pound  by  this 
number.     For  example,  taking  round  steak  again:  890-7-1000 
=  .89.     25   cents  divided  by  .89  =  28  cents,   the  cost   of   1000 
calories. 

3.  After  you  have  worked  out  these  results  for  all  the  foods, 
answer  the  following  questions  from  a  study  of  the  figures. 

Which  are  the  seven  cheapest  protein  foods  ? 
Which   are  the  seven  most   expensive  foods?     Write  them 
down  in  order  in  the  table  given  on  page  76. 

4.  Which  are  the  seven  cheapest  foods  for  fuel  value  ?    Which 
are  the  seven  most  expensive?     The  remainder  may  be  called 
medium-priced  foods. 

5.  In  general  which  are  the  cheaper  foods,  animal  or  vege- 
table? 

6.  Are  there  any  foods  which  are  found  in  both  lists  of  cheap- 
est foods  ?     Are  there  any  found  in  both  lists  of  most  expensive 
foods  ?  » 

7.  Record  your  answers  to  the  above  questions  in  the  fol- 
lowing tabular  form,  showing  relative  cheapness  of  foods. 


76 


SCIENCE  OF  HOME  AND   COMMUNITY 


COST  OF  PROTEIN 

COST  OF  FUEL  VALUE 

Cheap 

Medium 

Expensive 

Cheap 

Medium 

Expensive 

Economy  of  cooking.  Proper  methods  of  cooking  may 
aid  much  in  food  economy.  Frequently  the  more  costly 
cuts  of  meat  are  more  expensive  simply  because  they  are 
more  tender,  and  yet  they  are  not  more  nutritious  than  the 
cheaper  meats,  which  by  proper  methods  of  cooking  may  be 
made  as  tender  and  palatable.  Another  means  of  economy 
has  to  do  with  the  treatment  of  food  after  it  is  purchased. 
The  bones  and  trimmings  of  meat  contain  appreciable 
amounts  of  nourishment,  and  these  may  be  used  in 
soups  and  stews  instead  of  being  thrown  away,  as  is  so 
often  done. 

Storing  eggs.  Another  means  of  economy  is  to  buy  foods 
when  they  are  abundant  and  cheap  and  store  them  for  later 
use.  This  may  easily  be  done  with  eggs.  These  are  most 
abundant  and  cheapest  during  the  spring  and  early  summer. 
They  may  be  secured  then  and  stored  for  winter  use.  A 
number  of  methods  of  storing  have  been  tried,  but  the  water- 
glass  method  has  proved  the  best.  This  is  used  in  the  pro- 
portion of  one  part  of  water  glass  to  ten  parts  of  water. 
The  water  should  first  be  boiled  and  allowed  to  cool.  A 
quart  of  water  glass  will  make  enough  mixture  to  cover  from 
15  to  20  dozen  eggs.  The  cost  of  the  mixture  averages 
about  three  cents  per  dozen  eggs,  not  counting  the  cost  of 
the  container.  Earthenware  crocks  or  wooden  pails  are  the 
most  satisfactory  containers.  The  solution  may  be  poured 
into  the  container  and  the  eggs  added  as  they  are  collected. 


THE  HYGIENE  OF  THE  DINING  ROOM  77 

Only  fresh,  clean  eggs  should  be  used.     The  container  should 
be  covered  and  stored  in  a  cool,  dry  cellar. 

These  eggs,  of  course,  do  not  compare  with  fresh  eggs  for 
table  use,  but  they  are  very  satisfactory  for  cooking  pur- 
poses. They  compare  favorably  with  the  average  egg 
bought  at  the  store  during  the  winter.  It  has  been  found 
that  they  keep  in  good  condition  for  six  or  eight  months. 
When  the  eggs  are  to  be  boiled,  stick  a  needle  through  the 
shell  at  the  large  end  of  the  egg  to  prevent  the  shell  from 
breaking. 

HOME  PROJECT  8 

Purpose.     To  store  eggs  for  winter  use. 

Directions.  Consult  with  your  parents  about  the  matter 
and  if  they  are  willing,  try  storing  some  eggs  at  your  home  as 
explained  above.  A  pint  of  water  glass  (costing  about  25  cents) 
will  preserve  from  8  to  TO  dozen  eggs. 


HOME  PROJECT  9 

Purpose.     To  distinguish  fresh  from  stale  eggs. 

Directions.  I.  By  candling.  Secure  a  large  shoe  box  and 
remove  the  ends.  Cut  a  hole  about  the  size  of  a  half  dollar 
in  one  side.  Place  the  box 
over  a  lamp  or  electric  bulb 
and  darken  the  room.  Hold 
the  egg  with  the  large  end 
up,  before  the  opening  in 
the  box.  Good  eggs  look 
clear  and  firm.  The  air  cell 
should  not  be  larger  than  a 
dime,  and  the  yolk  may  be 
seen  dimly.  If  the  air  cell 

is  large  and  the  yolk  looks 

,     ,    *  •       x  1  FlG-  29-  —  Candhng  eggs, 

dark,  the  egg  is  stale.     If 

the  shell  contents  appear  very  dark,  the  egg  is  unfit  for  food. 


78  SCIENCE  OF  HOME  AND   COMMUNITY 

2.  By  the  use  of  salt  solution.  Make  a  ten  per  cent  salt 
solution.  Place  an  egg  in  it.  If  it  floats  it  is  stale. 

Amount  of  food  needed.  Our  next  question  as  to  how 
much  food  a  person  should  eat  is  a  practical  one  that  concerns 
us  at  every  meal.  In  answering  this  question  we  may  look 
at  it  from  two  standpoints ;  first,  with  reference  to  the  num- 
ber of  calories  the  body  needs,  and  second,  the  amount  of 
protein  it  needs. 

Number  of  calories  needed.  The  number  of  calories  used 
under  varying  circumstances  has  been  accurately  measured 
by  means  of  a  calorimeter.  This  is  an  apparatus  so  arranged 
that  it  will  measure  the  amount  of  heat  given  off  by  the 
various  activities  of  a  person  confined  in  a  small  room. 
When  a  person  is  at  rest,  the  activities  of  the  vital  organs 
(heart,  lungs,  etc.),  require  a  certain  number  of  calories. 
This  is  found  to  be  about  twelve  calories  a  day  for  each 
pound  of  body  weight,  or  about  1800  calories  for  a 
man  weighing  150  pounds.  This  is  the  fundamental 
basal  requirement  for  every  diet.  All  voluntary  mus- 
cular work  requires  additional  food  in  order  to  furnish  extra 
calories. 

The  number  of  calories  required  during  a  day  by  a  person 
depends  on  weight,  activity,  and  age.  The  larger  a  person, 
the  more  food  he  needs  if  the  weight  is  due  to  tissue  and  not 
to  excessive  fat.  The  number  of  calories  depends  very 
noticeably  on  the  muscular  activity  of  the  person.  It  in- 
creases rapidly  as  the  work  done  becomes  more  severe. 
Exercise  is  often  classified  into  four  groups  :  light,  moderate, 
active,  and  severe.  Men  of  sedentary  occupation,  such  as 
teachers  and  bookkeepers,  take  light  exercise ;  mail  carriers 
and  carpenters,  moderate  exercise ;  farmers  and  black- 
smiths, active  exercise ;  and  soldiers  and  lumbermen,  severe 
exercise.  The  following  table  shows  how  the  number  of 
calories  depends  on  the  exercise. 


THE  HYGIENE  OF  THE  DINING  ROOM 


79 


KINDS  OF  ACTIVITY 


CALORIES  PER  POUND  PER  HOUR 


Sleeping 

Sitting  quietly     . 
Standing    . 
Light  exercise 
Moderate  exercise 
Active  exercise    . 
Severe  exercise    . 


•5 
.6 

i 

1.25-1.5 

1-75-2 

X  or  more 


The  number  of  calories  needed  by  persons  under  varying 
conditions  of  activity  has  been  closely  determined,  and 
there  is  quite  general  agreement  on  the  essentials  for 
the  heat  requirements.  This  is  shown  in  the  following  table. 

DAILY  CALORIE  REQUIREMENTS 
For  Adults 


OCCUPATION 

CALORIES  PER  POUND  OF 
WEIGHT 

TOTAL  FOR  MAN  OF  150 
POUNDS 

(Approximate) 

Sedentary  (Professional  man) 

17 

2500 

Moderate  exercise  (Carpenter) 

20 

3000 

Active  (Farmer)     

24 

3500 

Severe  (Soldier)      

27 

4000 

For  Boys  and  Girls 


14  years  old  
15  years  old  
16  years  old  

24 

22 
°O 

17  years  old  

IS 

A  person  may  find  his  calorie  requirement  by  multiplying 
his  weight  by  the  appropriate  figure  in  the  above  table. 
Women  usually  require  less  than  men  because  they  weigh 
less  and  perform  less  vigorous  work. 


8o  SCIENCE  OF  HOME  AND   COMMUNITY 

More  calories  in  proportion  to  the  weight  are  needed  for 
children  than  for  adults.  For  the  two-year-old  child  about 
40  calories  per  pound  are  required.  This  number  gradually 
decreases  to  about  20  at  the  age  of  16. 

In  old  age  the  number  of  calories  needed  is  less  than  during 
middle  age.  This  decrease  runs  from  10  per  cent  at  60  years 
of  age  to  30  per  cent  for  those  over  80  years  of  age. 

Protein  requirements.  Having  noted  the  heat  require- 
ments of  the  body,  we  may  next  ask  how  much  protein  food 
the  body  needs.  While  protein  as  well  as  fats  and  carbo- 
hydrates furnishes  energy,  it  is  better  to  meet  these  heat 
requirements  through  the  use  of  fats  and  carbohydrates, 
and  to  provide  protein  only  for  the  repair  of  the  body  tissues. 
We  have  seen  that  the  calorie  requirement  of  the  body  de- 
pends on  weight,  age,  and  activity.  The  protein  require- 
ment depends  on  weight  and  age,  but  not  on  activity.  A 
man  when  he  is  doing  severe  muscular  work  has  the  same 
protein  requirements  as  when  he  is  doing  light  work. 

While  there  is  quite  general  agreement  among  authorities 
regarding  the  number  of  calories  needed  by  the  body,  there 
is  a  difference  of 'opinion  regarding  the  amount  of  protein 
needed.  There  are  two  schools,  one  favoring  a  low  protein 
diet,  and  the  other  favoring  a  high  protein  diet.  The  stand- 
ard set  by  the  first  school  for  a  man  of  150  pounds'  weight 
is  60  grams  (about  2  ounces)  daily :  the  standard  set  by  the 
second  school  is  about  100  grams  (about  3^  ounces). 

Chittenderi's  experiments.  Professor  Chittenden  of  Yale 
University  is  an  exponent  of  the  first  school.  During  1903 
and  1904  he  carried  on  a  series  of  experiments  to  test  the 
effect  of  a  low  protein  diet.  He  selected  for  this  purpose 
men  representing  a  variety  of  occupations :  soldiers,  college 
athletes,  and  college  professors.  The  experiment  lasted  for 
6  months.  During  the  first  month  the  foods  were  gradually 
Changed  so  as  to  include  smaller  quantities  of  proteins,  until 
during  the  last  5  months  the  diet  contained  less  than  half 


THE  HYGIENE  OF  THE  DINING  ROOM 


81 


as  much  protein  as  did  the  diet  to  which  they  had  been 
accustomed.  During  this  period  the  men  retained  their 
bodily  weight,  improved  in  general  health,  and  showed  a 
remarkable  gain  in  strength. 

The  following  table  showing  how  much  of  certain  foods 
will  furnish  two  ounces  of  protein  is  taken  from  Professor 
Chittenden's  report.  Of  course  it  would  be  very  unwise  to 
use  only  one  kind  of  food  to  furnish  this  protein,  but  the 
table  will  show  the  relative  value  of  different  foods  in  furnish- 
ing protein.  The  foods  are  arranged  in  the  order  of  the 
proportion  of  proteins,  those  containing  the  most  being 
placed  first. 


60  GRAMS  OR  2  OUKCES  or  PROTEIN  ARE  CONTAINED  IN 

FUEL  VALUE 
CALORIES 

£  lb.  fresh  lean  beef  loin      
\  lb.  salt  codfish,  boneless  
\  lb.  American  pale  cheese 

608 

245 
IO27 

\  lb.  dried  peas      

827 

|  lb.  dried  beans    
•|  lb.  uncooked  oatmeal 

963 
I  CCQ 

•3  lb.  lean  smoked  bacon      

I82O 

9        hen's  eggs 

72O 

ij  lb.  shredded  wheat      

212^ 

if  lb.  white  wheat  bread       
if  lb.  peanuts 

1520 

•2284. 

i|  lb.  baked  beans  
4  lb.  (2  quarts)  milk 

1125 
I3OO 

10  lb.  bananas      

4.6OO 

10  lb.  grapes 

AT.OO 

ii  lb.  lettuce  

QQO 

•2-j  lb   aooles 

QC7Q 

From  this  table  it  will  be  noted  that  the  foods  in  the  first 
part  of  the  table  which  furnish  the  largest  proportion  of 
protein  have  a  low  fuel  value ;  while  the  foods  in  the  latter 
part  of  the  table,  which  have  a  high  fuel  value,  furnish  only 
small  quantities  of  protein.  Here  again  we  may  see  the  need 
of  including  a  variety  of  foods  in  our  diet. 


82  SCIENCE  OF  HOME  AND   COMMUNITY 

Fisher's  experiments.  Another  set  of  experiments  was 
carried  on  at  Yale  by  Professor  Fisher.  His  purpose  was 
to  test  Mr.  Fletcher's  claim  that  thorough  mastication  com- 
bined with  obedience  to  appetite  leads  naturally  to  the 
selection  of  the  proper  amounts  of  food.  The  results  have 
a  bearing  on  the  question  of  the  protein  requirements. 
Nine  students  took  part  in  the  experiment,  which  lasted  5 
months.  Two  rules  were  followed :  first,  to  masticate  the 
food  thoroughly,  and  second,  to  follow  the  appetite  regarding 
the  amount  and  kinds  of  food  eaten.  At  the  end  of  the 
experiment  it  was  found  that  they  were  eating  only  one  half 
as  much  protein  as  they  had  been  accustomed  to  eat.  Tests 
of  endurance  were  made  both  at  the  beginning  and  end  of 
the  experiment,  and  it  was  found  at  the  end  that  there  was  an 
enormous  increase  in  the  power  of  endurance.  The  men  no- 
ticed, too,  a  general  improvement  in  health  and  mental  ability. 

These  experiments  show  that  men  can  live  on  a  low  pro- 
tein diet  and  remain  in  good  health  or  even  improve  in  health 
and  physical  condition. 

The  other  school,  which  favors  a  high  protein  diet,  points 
to  the  dietary  studies  which  have  been  made  in  many 
countries  which  show  that  these  people  are  living  on  a  high 
protein  diet.  And  they  claim  that  while  a  person  can  live 
on  a  low  protein  diet,  it  is  dangerous  to  health  to  continue 
to  do  so  for  long  periods  of  time. 

General  conclusions.  As  far  as  the  author  has  studied 
the  question  it  seems  to  him  that  the  low  protein  school  has 
the  better  of  the  argument.  It  points  out  that  these  studies 
of  dietaries  simply  show  what  people  prefer  to  eat,  but  do 
not  show  what  is  best  for  them  to  eat.  Young  children  would 
prefer  to  live  largely  on  candy  if  allowed  to  follow  their 
inclinations,  but  this  does  not  prove  that  this  is  the  best 
diet  for  them. 

There  seems  to  be  a  general  tendency  to  take  a  position 
midway  between  these  extreme  views,  to  avoid  on  one  hand 


THE  HYGIENE  OF  THE  DINING  ROOM  83 

the  possible  danger  of  a  lack  of  sufficient  protein,  and  on 
the  other  to  avoid  the  dangers  from  an  excessive  use  of  pro- 
teins as  evidenced  in  a  too  free  indulgence  in  meat.  Be- 
tween the  two  extremes  of  60  grams  and  100  grams  as  the 
daily  requirement  of  protein,  a  standard  is  being  set  of  75 
grams  for  a  man  of  1 50  pounds'  weight,  that  is,  one  half  a  gram 
of  protein  for  each  pound  of  weight.  So  that  an  adult  may 
find  his  protein  requirement  in  grams  by  multiplying  his 
weight  by  one  half. 

Children,  on  account  of  the  formation  of  new  tissues, 
require  a  larger  proportion  of  protein.  This  ranges  between 
one  gram  and  three  quarters  of  a  gram  for  each  pound  of 
weight. 

Determination  of  adequacy  of  diet.  After  a  standard  has 
been  set  as  to  how  much  protein  and  how  many  calories  a 
person  needs  daily,  how  may  one  know  whether  his  diet 
approximates  this  standard?  This  may  be  determined  in 
three  ways,  by  one's  weight,  by  one's  appetite,  and  by 
the  use  of  food  tables  that  have  been  prepared  for  this 
purpose. 

Use  of  food  tables.  A  person  first  makes  out  for  one  day 
a  list  of  the  kinds  of  foods  eaten  and  the  approximate  quan- 
tities in  terms  of  common  servings.  By  studying  the  food 
table  given  on  pages  85  and  86  one  may  determine  the  weight 
of  protein  and  the  number  of  calories  in  each  serving  of  food. 
These  may  be  added  and  thus  the  total  obtained  for  the  day. 
Such  changes  in  the  diet  may  be  made  as  are  needed  to  bring 
it  more  closely  in  accord  with  the  standard.  It  is  well  to 
make  such  a  study  of  one's  daily  food  several  times  a 
year. 

The  following  sample  diet  is  given  as  showing  the  method 
of  working  out  the  food  value.  This  is  a  sample  of  a  low 
protein  diet  used  by  Professor  Chittenden  in  his  experiments, 
to  which  reference  has  already  been  made. 


84 


SCIENCE  OF  HOME  AND   COMMUNITY 


BREAKFAST 


SERVING 

WEIGHT 

PROTEIN 

CAJ.ORIES 

One  shredded  wheat  biscuit  .  . 
One  teacup  of  cream  

30  grams 
1  20  grams 
57  grams 
38  grams 
100  grams 
30  grams 
10  grams 

3.15  grams 
3.12  grams 
5.07  grams 
0.38  gram 
0.26  gram 
0.78  gram 

1  06 
206 

165 

284 

51 

38 

850 

One  water  roll 

Two  one-inch  cubes  of  butter  .  . 
Three  fourths  cup  of  coffee  .  . 
One  fourth  teacup  of  cream  .  . 
One  lump  of  sugar  

12.76  grams 

LUNCH 


One  teacup  home-made  chicken 
souo 

IAA  grams 

5  2?  prams 

60 

One  Parker-house  roll     .... 
Two  one-inch  cubes  of  butter  .     . 
One  slice  lean  bacon  

38  grams 
38  grams 
10  grams 

3.38  grams 
0.38  gram 
2  14  grams 

no 

284 
6s 

One  small  baked  potato      .     . 
One  rice  croquette 

60  grams 
90  grams 

1.53  grams 
3  A  2  crams 

55 

T  CO 

•ff.fi 

•28 

3° 

1  6.  10  grams 

928 

DINNER 


One  teacup  cream  of  corn  soup    . 
One  Parker-house  roll     .... 
One-inch  cube  of  butter      .     .     . 
One  small  lamb  chop,  broiled,  lean 
meat 

130  grams 
38  grams 
19  grams 

30  grams 

3.25  grams 
3.38  grams 
0.19  gram 

8  51  grams 

72 
no 
142 

02 

One  teacup  of  mashed  potato 
Apple-celery-lettuce    salad    with 
mayonnaise  dressing   .... 
One  Boston  cracker,  split,  2  inches 
diameter 

167  grams 
50  grams 
12  grams 

3.34  grams 
0.62  gram 
i  32  grams 

175 

75 

4.7 

One    half-inch    cube    American 
cheese 

12  grams 

-i  -ic  grams 

en 

One  half  teacup  of  bread  pudding 

85  grams 

5.25  grams 

150 

18 

3° 

2Q.2I  erams 

051 

Total  for  day 

58.07  grams 

27^0 

THE  HYGIENE  OF  THE  DINING  ROOM  85 

• 

The  following  table  gives  the  protein  and  fuel  value  of  a 
few  common  foods  as  served  on  the  table. 


TABLE  OF  FOOD  VALUES 


NAME  OF  FOOD 

PORTION  EATEN 

WEIGHT 
(Grams) 

AMOUNT  OF 
PROTEIN 
(Grains) 

CALORIES 

Vegetables 

Beans,  baked,  canned 

Small  side  dish  .     . 

75 

5-2 

IOO 

Beets  

One  serving  . 

82 

1.9 

35 

Cabbage  

One  serving  .     .     . 

103 

.2 

35 

Corn,  sweet,  cooked  . 

One  side  dish 

99 

2.8 

IOO 

Lettuce    

One    fourth    small 

head      .... 

65 

•7 

12 

Onions,  cooked 

One  large  serving     . 

120 

1.2 

50 

Peas,  green,  cooked    . 

One  serving    .     .     . 

85 

5-7 

IOO 

Potatoes,  boiled    . 

One  large-sized  . 

102 

2-5 

IOO 

String  beans     .     .     . 

One  serving  . 

96 

.8 

20 

Tomatoes,  fresh    . 

One  average  .     .     . 

120 

i 

25 

Fruits 

Apple 

One  apple 

TQ1 

er> 

Banana 

One  large  .... 

*3 
IOO 

-j 

3" 

IOO 

Cantaloupe  .... 

Ordinary  serving     . 

500 

•o 

•4 

2OO 

Grapes 

Small  bunch 

1  16 

A 

IOO 

Orange     .... 

One  large  .... 

io^J 
27O 

•T" 

.6 

IOO 

Peaches 

One  ordinary 

4,  j  \j 

QC 

7 

•1C 

7O 

•/ 

oo 

Pears  

One  large  .... 

I7"? 

IOO 

Prunes 

Three  large 

1  /o 
^2 

•7 

IOO 

o^ 

•o 

Raspberries,  red    .     . 

One  serving  . 

I78 

1.8 

IOO 

Strawberries 

One  serving  .     .     . 

130 

i.i 

50 

Cooked  Meats 

Beef,  roasted     .     .     . 

Small  serving 

37 

8.1 

2OO 

Lamb  chops      .     .     . 

One  small  chop  . 

27 

8-5 

IOO 

Leg  of  mutton  . 

Large  serving     .     . 

34 

8-5 

IOO 

Oysters  (raw)    . 

Six  

OS 

c  7 

CQ 

Pork,  roasted,  lean    . 

Small  serving     .     . 

vo 
34 

o  / 
7-9 

o** 

IOO 

Sirloin  steak 

Small  steak    . 

40 

9.6 

IOO 

86 


SCIENCE  OF  HOME  AND   COMMUNITY 


NAME  or  FOOD 

PORTION  EATEN 

WEIGHT 
(Grams) 

AMOUNT  or 
PROTEIN 
(Grams) 

CALORIES 

Cereals 

Bread,  brown   .     .     . 

Thick  slice     .     .     . 

43 

2.2 

IOO 

Bread,  white     . 

Ordinary  thick  slice 

38 

3-5 

100 

Cream  of  wheat     .     . 

One  helping  . 

140 

3-1 

IOO 

Corn  flakes,  toasted  . 

Ordinary  dish     . 

27 

I.9 

IOO 

Hominy 

Large  serving 

I2O 

2  A. 

IOO 

Macaroni,  cooked 

Ordinary  serving     . 

110 

*  *tr 

3-3 

IOO 

Oatmeal 

One  serving  . 

IO^ 

2  Q 

6^ 

Parker-house  roll  . 

One  roll     .... 

A  WO 

45 

^..y 

4 

O 

140 

Rice,  boiled 

Ordinary  cereal  dish 

87 

2.4 

IOO 

Shredded  wheat     .     . 

One  biscuit    .     .     . 

27 

2.8 

IOO 

Dairy  Products 

Butter      

One-inch  cube    .     . 

19 

.2 

150 

Cheese,  American 

One  half-inch  cube 

12 

3-3 

5<* 

Milk    

One  glass  (£  pint)  . 

225 

6.8 

1  60 

Nuts 

Peanuts  

Six  double      .     .     . 

9 

2.4 

50 

Walnuts,  California    . 

Three   

7 

1.2 

50 

Cakes,  Pastry,  Pud- 

dings 

Cake,  chocolate  layer 

Ordinary        square 

piece      .... 

55 

3-4 

200 

Cake,  sponge    . 

Small  piece    .     .     . 

25 

1.6 

IOO 

Cookies,  sugar  . 

One  cookie     . 

17 

1.2 

75 

Doughnut    .... 

One  doughnut    . 

46 

3 

200 

Pie,  apple     .... 

Ordinary  piece  .     . 

100 

3-6 

300 

Pie,  custard 

Ordinary  piece  . 

104 

4.4 

300 

Pie,  lemon    .... 

Ordinary  piece  . 

H5 

4.2 

300 

Pudding,  cream  rice  . 

Very  small  serving 

75 

3 

IOO 

Miscellaneous 

Clam  chowder  .     . 

One  plate  .... 

H5 

2 

50 

Egg,  hen's,  boiled 

One  large  egg     .     . 

58 

7.8 

IOO 

Soup,  bean  .... 

Very  large  plate 

150 

4.8 

IOO 

Sugar 

One  teaspoonful 

8 

o 

T.T. 

oo 

THE  HYGIENE  OF  THE  DINING  ROOM 


87 


HOME  PROJECT  10 

Purpose.  To  find  out  if  you  are  eating  the  right  kinds  and 
amount  of  food. 

Directions,  i.  Keep  a  careful  record  for  one  day  of  the 
kinds  and  amounts  of  food  that  you  eat  for  each  meal.  In 
recording  the  amounts  use  the  terms  found  in  the  second  column 
of  the  table  on  pages  85  and  86.  Bring  these  figures  to  school 
and  by  the  help  of  the  instructor  work  out  the  following  directions. 

2.  By  means  of  the  table  find  (a)  the  weight  of  protein  and 
(&)  the  fuel  value  in  calories  of  each  portion  of  food  eaten. 
Record  them  in  the  following  tabular  form  which  should  be 
copied  in  your  notebook.  (See  page  84.) 


KIND  OF  FOOD 

PORTION  EATEN 

WEIGHT  OF  PROTEIN 
(Grams) 

FUEL  VALUE 
(Calories) 

Breakfast  .... 
Dinner  
Supper 

Total  

3.  To  find  the  number  of  grams  of  protein  required  daily  by 
your  body,  multiply  your  weight  by  three  quarters. 

4.  To  find  the  number  of  calories  needed,   multiply  your 
weight  by  the  number  given  on  page  79  to  correspond  with 
your  age. 

5.  Compare  these  two  results  with  the  two  found  above. 
What  changes  can  you  make  in  your  diet  to  make  it  conform 
more  nearly  with  the  standard  given  ? 

6.  Using  the  table  on  pages  85  and  86  make  out  a  diet  for 
yourself  for  the  three  meals  for  one  day  that  shall  meet  the 
standard  you  require.     Make  the  record  in  the  same  form  as 
above.     Make  several  diets  each  of  which  meets  your  require- 
ments. 

7.  Also,  compare  your  weight  with  the  average  for  your  height. 

Appetite  as  a  guide.     The  common  method  of  determining 
the  amount  of  food  we  need  is  to  eat  till  the  appetite  is 


88  SCIENCE  OF  HOME  AND   COMMUNITY 

satisfied.  Is  the  appetite  a  safe  guide?  We  can  be  sure 
that  it  is  not  always  so,  because  we  think  at  once  of  children 
who  eat  excessive  amounts  of  candy  and  of  drunkards  who 
drink  excessive  amounts  of  alcoholic  liquors.  Many  people 
have  acquired  an  unnatural  appetite  for  various  kinds  of 
foods, that  is  not  to  be  trusted.  In  the  main  a  natural  ap- 
petite is  a  safe  guide  to  follow.  If  a  person  has  not  such  an 
appetite,  one  way  of  securing  it  is  to  practice  thorough 
mastication  of  food.  This  means  that  the  food  should  be 
chewed  till  it  becomes  so  fine  that  it  naturally  passes  down 
the  throat  without  conscious  effort  of  swallowing.  At 
first  this  will  require  thought  to  overcome  a  habit  of  hasty 
eating,  but  with  a  little  attention  the  habit  of  thorough 
mastication  may  be  acquired.  When  this  point  is  reached, 
it  may  be  said  in  general  that  a  person  may  then  allow  him- 
self to  be  governed  by  his  appetite  both  as  regards  the 
amounts  and  kinds  of  foods  to  be  eaten.  But  even  under 
these  conditions  a  person  should  keep  in  mind  some  general 
principles  regarding  the  kinds  and  amounts  of  foods  that 
the  body  needs. 

It  is  the  experience  of  many  people  who  follow  this  practice 
that  they  naturally  choose  a  low  protein  diet.  Even  when 
one  has  acquired  the  habit  of  thorough  mastication,  it  is 
well  to  make  an  occasional  study  of  one's  diet  by  means  of  a 
table  as  previously  explained. 

Weight  as  a  guide.  Another  method  that  gives  some  in- 
dication of  the  correctness  of  the  diet  is  to  note  a  person's 
weight  in  comparison  with  the  average  for  the  given  height 
and  age.  If  one  is  storing  up  a  large  surplus  of  fat,  this 
shows  that  he  is  eating  too  much  food.  A  reduction  in 
weight  should  be  brought  about  gradually  and  under  the 
advice  of  a  physician. 

Failure  to  store  up  fat  does  not  necessarily  mean  that  the 
person's  diet  is  correct,  because  protein  food  is  not  stored  up, 
but  the  excess  of  nitrogen  is  eliminated  through  the  kidneys. 


THE  HYGIENE  OF  THE  DINING  ROOM 


People  may  eat  meat  to  excess  and  yet  not  show  it  by  storing 
up  fat. 

Balancing  the  diet.  The  following  table  taken  from  a 
recent  government  publication  will  be  helpful  in  planning 
a  well-balanced  diet. 

Food  Elements 
Eat  something  from  each  of  these  five  groups  every  day : 


Group  I. 
lators. 

Group  II. 


Foods  for  mineral  matter,  acids,  and  body  regu- 


Protein  foods. 


Group  III.   Starchy  foods. 
Group  IV.    Foods  for  sugar. 
Group  V.      Foods  for  fat. 


Eat  vegetables  and 
regulators. 
Apples 
Apricots 
Asparagus 
Bananas 
Lima  beans 
Beets 

Blackberries 
Cabbage 
Carrots 
Cauliflower 
Celery 


GROUP  I 

fruits  for  mineral  matter,  acids,  and  body 


Canned  or 

Green  corn 
Cucumbers 
Grapes 
Lemons 
Lettuce 
Muskmelon 
Onions 
Oranges 
Parsnips 
Peaches 


Pears 
Green  or 

Canned  peas 
Pineapple 
Rhubarb 
Spinach 
Squash 
Strawberries 
String  beans 
Tomatoes 
Turnips 


Beans 

Soy 

Lima 

Navy 
Beef 
American  cheese 


GROUP  II 

Eat  these  foods  for  protein. 

Cottage  cheese  Lamb  Peanuts 

Eggs  Skim  milk  Peas 

Fish  Mutton  Pork 

Fowl  Nuts  Rabbits 

Game  Oysters  Veal 


9o 


SCIENCE  OF  HOME  AND   COMMUNITY 


Barley 
White  bread 
Cake 
Green  or 

Canned  corn 
Corn  flakes 
Corn  meal 
Soda  crackers 


Dried  apples 
Cane  sirups 
Corn  sirup 
Dates 


Bacon 
Butter 
Chocolate 
Cocoa 


GROUP  III 

Eat  these  foods  for  starches. 
Graham  crackers 
Cream  of  Wheat 
Farina 
Wheat  flour 
Hominy 
Macaroni 
Oatmeal 
Rolled  oats 

GROUP  IV 

Eat  these  foods  for  sugar. 
Honey 
Maple  sirup 
Molasses 
Dried  peaches 

GROUP  V 

Eat  these  foods  for  fat. 
Corn  oil 
Cream 
Lard 
Oleomargarine 


White  potatoes 
Sweet  potatoes 
Rice 
Rye 
Tapioca 

Wheat  breakfast 
foods 


Prunes 
Raisins 
Sorghum 
Sugar 


Olive  oil 
Peanut  butter 
Peanut  oil 
Salt  pork 


Method  of  eating.  Mastication  is  the  first  step  in  the 
digestive  process,  and  as  this  influences  the  later  stages  of 
the  process,  it  is  essential  that  food  should  be  thoroughly  and 
completely  masticated.  This  mastication  prepares  the  food 
for  swallowing :  it  breaks  it  up  into  small  particles  so  that  the 
digestive  juices  of  the  stomach  can  act  upon  it  more  readily  ; 
it  increases  the  flow  of  the  gastric  juice ;  and  it  mixes  the 
saliva  with  the  food  so  that  the  process  of  digesting  the 
starch  begins.  Since  this  process  stops  soon  after  the  food 
reaches  the  stomach,  it  is  important  that  the  food  should 


THE  HYGIENE  OF  THE  DINING  ROOM 


91 


U.S.  Department  of  Agriculture 

Office  of  Experiment  Stations 

A.  C.  True:  Director 


Prepared  by 
C.  F.  LANGWORTHY 
Expert  In  Charge  of  Nutrition  Investigations 


COMPOSITION  OF  FOOD  MATERIALS. 


Fuel  Value 


Protein  Fat         Carbohydrates         Ash  Water 

WHITE  BREAD  WHOLE  WHEAT  BREAD 

Jyyater:35.3    Water;38 

VoteinrS.S     Protein^9.7 


FUEL  VALUE: 


Carbo-  Carbo. 

tes:53.1     hydrates:  49 

OAT 
BREAKFAST    FOOD 

COOKED 


FUEL    VALUE: 


1215  CALORIES      Water84.5 

PER  POUND 

Proteir2.8 


TOASTED  BREAD 

AshToT^ 


1 1  40  CALORIES 
PER  POUND 

Fat:  0.5 

Carbohydrates:  11. 5 


CORN  BREAD 


ater:.24.0        Water:38.9 


285  CALORIES 
PER  POUND 


Votein:  11.5        Protein:  7.9 

:3  Carbo-  Carb^^^ 

jj  hydrates:  61 .2          hydrates:46.3 


MACARONI 

COOKED 

Fat:  1.5     Protein: 3.0    ^-Water:78.4 


FUEL    VALUE: 


1420  CALORIES 
PER  POUND 

Ash:  1J 
Carbo- 


1205CALORIES 
PER  POUND 


hydrates:  15. 


VALUE: 


41  5  CALORIES 
PER  POUND 


FIG.  30.  —  Composition  of  bread. 


92  SCIENCE  OF  HOME  AND   COMMUNITY 

remain  in  the  mouth  long  enough  for  the  process  to  get 
well  started.  We  have  seen,  furthermore,  that  thorough 
mastication  helps  one  to  develop  a  natural  appetite  that 
serves  as  a  guide  in  eating. 

Overeating.  Overeating  and  mastication  are  closely  re- 
lated, because  insufficient  mastication  tends  towards  over- 
eating and  one  of  the  chief  reasons  for  emphasizing  thorough 
mastication  is  to  avoid  the  ills  resulting  from  overeating. 
Many  digestive  ills  are  due  to  eating  more  food  than  the 
body  needs ;  this  is  especially  true  in  the  cases  of  those 
people  who  lead  a  sedentary  life,  which  involves  little  mus- 
cular exercise. 

As  a  result  of  taking  too  much  food  into  the  stomach,  that 
organ  is  not  able  to  take  care  properly  of  its  contents,  so 
that  the  food  remains  a  long  time  in  the  stomach.  There  it 
may  begin  to  decay  and  give  off  gases  that  may  cause  stomach 
trouble.  The  whole  digestive  system,  —  stomach,  intes- 
tines, and  the  organs  connected  with  them,  —  is  overworked 
to  get  rid  of  the  excess  of  food.  Those  systems  which  care 
for  the  food  after  it  is  digested  and  used,  the  absorptive 
and  excretory  systems,  are  overtaxed  so  that  they  become 
weakened.  The  kidneys  in  particular  are  strained  by  the 
extra  work  required  in  throwing  off  the  excess  of  nitrogenous 
waste  matter,  due  to  eating  too  much  protein  food.  The 
working  of  the  whole  machinery  of  the  body  is  hindered 
by  the  excessive  work  demanded  of  it,  and  its  action  is 
clogged  by  the  excess  of  food.  As  a  result,  the  general 
efficiency  of  the  body  is  lowered  and  the  health  impaired. 

Sir  Henry  Thompson,  a  noted  English  physician,  says, 
"  I  have  come  to  the  conclusion  that  more  than  half  the 
disease  which  embitters  the  middle  and  latter  part  of  life 
is  due  to  avoidable  errors  in  diet,  and  that  more  mischief 
in  the  form  of  actual  disease,  of  impaired  vigor,  and  of 
shortened  life  accrues  to  civilized  man  in  England  and 
throughout  Central  Europe  from  erroneous  habits  of  eating 


THE  HYGIENE  OF  THE  DINING  ROOM  93 

than  from  the  habitual  use  of  alcoholic  drink,  considerable 
as  I  know  that  evil  to  be." 

The  point  to  be  emphasized  in  this  quotation  is  that  these 
diseases  are  due  largely  to  avoidable  errors  in  diet ;  that  isr 
these  diseases  might  be  largely  escaped  by  proper  methods 
of  eating.  The  ills  resulting  from  improper  methods  do  not 
show  themselves  all  at  once  but  accumulate  gradually 
through  years  as  the  digestive  system  becomes  weakened  y 
so  that,  as  noted  in  the  statement  above,  these  diseases  are 
specially  prevalent  in  the  middle  and  latter  part  of  life. 
On  account  of  these  slowly  accumulating  ills,  it  is  very  easy 
for  one  to  overlook  them  for  a  while  ;  but  for  this  very  reason 
it  is  very  important  that  one  should  guard  against  them  in 
youth  before  it  is  too  late.  Some  of  these  diseases  which 
are  so  prevalent  but  which  might  be  largely  avoided  by 
proper  eating,  are :  dyspepsia  or  indigestion  in  its  many 
forms,  jaundice,  gout,  colic,  cholera  morbus,  constipation, 
and  appendicitis.  Statistics  show  that  the  death  rate  in 
this  country  for  people  over  forty  is  increasing.  Mistakes 
in  eating  undoubtedly  constitute  one  cause  for  this  increas- 
ing death  rate. 

Care  of  the  teeth.  As  thorough  mastication  of  food  is 
such  an  important  factor  in  its  effect  on  health,  we  can 
understand  how  important  it  is  that  the  teeth  should  be. 
well  cared  for,  so  that  they  may  be  preserved  in  good  con- 
dition to  perform  the  work  of  mastication.  There  are  three 
factors  concerned  in  the  decay  of  teeth :  first,  the  food 
particles  that  lodge  between  the  teeth ;  second,  the  bacteria 
that  act  on  these  food  particles  ;  and  third,  the  acid  produced 
as  a  result  of  this  action.  These  acids  act  on  the  teeth 
and  produce  decay.  To  prevent  this  decay,  a  person  should 
see  to  it  that  particles  of  food  are  not  allowed  to  lodge  be- 
tween the  teeth.  The  first  step  in  the  care  of  the  teeth  is 
thorough  mastication,  which  leaves  the  teeth  cleaner  than 
does  insufficient  mastication.  The  larger  pieces  of  food  may 


94  SCIENCE  OF  HOME  AND   COMMUNITY 

be  removed  by  means  of  toothpicks  or  dental  floss,  but  the 
smaller,  tiny  particles  require  the  use  of  a  toothbrush.  The 
best  time  to  brush  the  teeth,  if  it  is  done  but  once  a  day,  is 
after  the  evening  meal.  Otherwise  the  food  particles  would 
remain  in  the  teeth  during  all  the  night,  thus  allowing  a  long 
time  for  the  action  of  the  bacteria  in  producing  decay.  But 
while  the  teeth  should  be  cleaned  at  least  once  a  day,  the 
best  care  requires  another  cleansing  after  the  morning  meal. 
The  value  of  a  toothpowder  lies  in  the  fact  that  it  contains 
substances  which  help  to  neutralize  the  acids  that  cause 
decay,  and  it  also  acts  as  an  antiseptic  on  the  bacteria. 

Sources  of  food.  All  of  our  food  is  made  either  directly 
or  indirectly  by  the  action  of  plants.  Some  of  our  food 
consists  of  the  flesh  of  animals,  but  these  animals  have  fed 
on  plant  food,  so  that  this  brings  us  back  to  plants  as  the 
final  source  of  our  food.  Starch  is  made  by  the  green  matter 
in  plants  known  as  chlorophyll,  generally  found  in  the  leaf. 
This  chlorophyll  takes  water  and  carbon  dioxid,  and  from 
this,  in  the  presence  of  light,  manufactures  starch.  The 
water  comes  up  from  the  roots  >  through  the  stem  and  the 
carbon  dioxid  passes  from  the  air  through  small  openings 
in  the  leaf.  This  starch  is  one  of  our  commonest  foods. 
Later,  some  of  this  starch  is  united  in  the  plant  with  sub- 
stances that  come  up  through  the  roots  from  the  soil,  and  by 
this  process  proteins  are  formed,  which  constitute,  as  we 
have  seen,  another  important  food  for  mankind. 

Summary.  The  whole  matter  of  the  hygiene  of  foods 
may  be  briefly  summarized  by  saying  that  a  thorough  masti- 
cation of  foods  will  help  develop  a  natural  appetite,  which 
will  decide  for  us  both  what  to  eat  and  how  much  to  eat. 
One  should  also  occasionally  compare  his  weight  with  that 
of  the  average  for  his  height ;  and  compare  his  daily  diet 
with  standards  that  have  been  set  as  a  result  of  experiments, 
so  that  he  may  know  whether  he  is  approximating  these 
standards.  As  general  guides  these  suggestions  may  be 


THE  HYGIENE  OF  THE  DINING  ROOM  95 


given :  Avoid  large  amounts  of  meat  foods.  Use  milk,  fruits, 
and  vegetables  freely. 

Drinking  water.  Water  should  be  drunk  freely  many 
times  a  day.  Recent  experiments  have  shown  that  drink- 
ing water  during  the  meals  really  helps  the  process  of  diges- 
tion instead  of  hindering  it,  as  has  sometimes  been  thought. 
Water  should  not  be  taken,  however,  when  the  mouth  con- 
tains food  and  used  as  a  substitute  for  mastication  to  wash 
down  foods  that  are  only  partially  masticated.  Under 
ordinary  conditions  a  person  needs  about  two  glasses  at  each 
meal,  and  two  glasses  between  meals,  or  eight  glasses  a  day, 
which  is  equal  to  about  two  quarts.  Other  drinks  such  as 
milk,  tea,  and  coffee  furnish  a  part  of  the  needed  water. 

Some  misnamed  foods.  There  are  some  drinks  which 
are  very  commonly  used  at  the  table  that  have  sometimes 
been  carelessly  called  foods,  namely  coffee  and  tea.  These 
are  not  foods  in  any  sense  of  the  word.  Both  are  stimu- 
lants that  act  as  a  spur  on  the  nervous  system  to  in- 
crease its  activities.  This  stimulative  effect  is  due  to  a 
drug  called  caffeine  in  coffee  and  theine  in  tea,  the  two  being 
almost  identical.  Both  also  contain  tannic  acid,  which  is 
very  harmful  to  the  membrane  of  the  stomach.  The  tannic 
acid  does  not  dissolve  in  water  as  readily  as  the  theine, 
and  the  effects  of  tea  are  less  harmful  if  the  water  is  not 
allowed  to  boil  after  the  tea  is  made  and  dissolve  the  tannic 
acid. 

Neither  tea  nor  coffee  serves  any  necessary  function  in  the 
body,  and  their  use  is  to  be  looked  on  as  an  indulgence. 
The  effect  of  these  drinks  on  adults  varies  greatly  with 
different  people.  Some  people  are  distinctly  harmed  by 
their  use,  while  others  seem  to  use  them  without  any  apparent 
injury.  One  of  the  worst  features  attending  the  use  of  tea 
and  coffee  is  the  possibility  that  one  may  acquire  an  appetite 
which  he  cannot  control  and  thus  become  a  slave  to  tea  and 
coffee.  But  whatever  may  be  said  about  their  effect  on 


96  SCIENCE  OF  HOME  AND   COMMUNITY 

adults,  all  authorities  agree  that  their  effect  is  injurious  on 
growing  boys  and  girls,  who  will  be  better  off  if  they  leave 
these  drinks  alone. 


SUPPLEMENTARY  QUESTIONS  FOR  CLASS  DISCUSSION 

1.  Which  is  better,  a  mixed  diet  or  a  vegetable  diet? 

2.  To  what  extent  should  cost  be  considered  in  buying  foods  ? 

3.  How   may   economy  be   practiced   without   injuring  the 
health? 

4.  How  did  Professor  Chittenden's  experiments  differ  from 
Professor  Fisher's? 

5.  To  what  extent  are  their  conclusions  similar? 

6.  How  may  these  experiments  help  us  in  determining  our 
food  habits  ? 

7.  What  is  the  chief  value  of  thorough  mastication  of  food? 

8.  What  bearing  on  health  does  the  care  of  the  teeth  have? 

9.  How  does  overeating  injure  health  ? 

HOME  PROJECT  n 

Purpose.     To  practice  daily  the  proper  health  habits. 

Directions.  Copy  the  following  table  in  your  notebook.  Try 
each  day  to  follow  out  the  habits  here  suggested.  At  the  end  of 
each  day  fill  in  the  blank  spaces,  giving  yourself  the  credits  you  de- 
serve according  to  the  faithfulness  with  which  you  have  practiced 
each  of  these  habits.  At  the  end  of  the  week  have  your  father 
or  mother  sign  the  report.  Then  hand  it  to  your  instructor  as 
a  part  of  your  regular  class  work  for  which  you  will  receive 
school  credit. 


THE  HYGIENE  OF  THE  DINING   ROOM 


97 


TABLE  OF  HEALTH  HABITS  FOR  THE  WEEK  ENDING  (date) 


DAILY 
CREDIT 

SUN. 

MON. 

TUBS. 

WED. 

THURS. 

FRI. 

SAT. 

Clean  teeth    .... 

19 

Sleep     with     window 

open  

19 

Retire  by  9.30  l  .     .     . 

19 

Abstain   from   use   of 

coffee  and  tea  . 

19 

Exercise   i    hour  out- 

doors     .... 

19 

Bathe  once  a  week  .     . 

5 

Total     

100 

I  believe  that  the  above  record  is  a  truthful  account  of  my  child's 
health  habits  for  the  week. 

(To  be  signed  by  parent.) 

SCHOOL  PROJECT  i 

Purpose.     To  form  a  League  of  Modern  Health  Crusaders. 

Directions.  Write  to  the  National  Association  for  the  Study 
and  Prevention  of  Tuberculosis,  105  East  226.  St.,  New  York 
City,  for  information  as  to  how  a  league  of  modern  health 
crusaders  may  be  formed.  Circulars  will  be  sent  giving  full 
particulars. 

REFERENCES 

Conley,    Nutrition  and  Diet,  American  Book  Co.,  New  York 

City. 
Fisher  and  Fisk,  How  to  Live,  Funk  and  Wagnalls  Co.,  New 

York  City. 

1  The  time  will  vary  according  to  the  age  of  the  child. 


CHAPTER  VI 
THE   SCIENCE   OF  THE   KITCHEN 

1.  In  what  ways  are  our  modern  methods  of 
cooking  better  than  the  methods  used  in  early 
times  ? 

2.  What  advantages  has  each  of  the  following 
methods  of  preserving  foods  over  the  other :  drying 
and  canning? 

Purposes  of  cooking.  Man  in  his  early  history  ate  his 
food  uncooked ;  but  to-day  civilized  man  finds  that  cooking 
foods  serves  three  important  purposes :  first,  it  destroys 
parasites  and  disease  germs;  second,  it  renders  the  food 
more  palatable  ;  and  third,  it  makes  the  food  more  digestible. 

Sometimes  bacteria  and  parasites  that  cause  disease,  such 
as  typhoid  fever  and  trichinosis,  are  found  in  foods  ;  but  the 
high  temperature  used  in  cooking  kills  these  dangerous  forms 
and  thus  renders  them  harmless.  Many  foods  are  made 
more  agreeable  to  the  taste  through  cooking,  and  this  has 
an  important  effect  on  the  digestion  of  the  food,  as  it  is  found 
that  foods  which  we  enjoy  are  digested  better  than  foods 
that  we  dislike. 

Many  foods  are  rendered  more  digestible  by  cooking. 
Much  of  the  starch  found  in  vegetable  foods  is  inclosed  in 
cellulose  walls,  upon  which  the  digestive  juices  cannot  act. 
Cooking  bursts  these  walls,  thus  allowing  opportunity  for 
the  digestive  juices  to  act  on  the  swollen  starch  granules. 
Cooking  softens  the  tough,  connective  tissues  of  some  meats, 
and  this  renders  them  more  tender  and  easily  digested. 

08 


THE  SCIENCE  OF  THE  KITCHEN  99 

Effect  of  heat  on  foods.  Heat  hardens  or  coagulates 
protein  foods  such  as  the  white  of  an  egg.  Fats  are  little 
effected  by  low  temperatures,  except  to  be  melted ;  but  at 
high  temperatures  they  are  decomposed  and  form  irritating 
substances  which  hinder  digestion.  The  chief  effect  of 
heating  starch  in  water  is  to  cause  a  swelling  of  the  starch 
granules.  Dry  heat  changes  the  starch  into  dextrin  and 
glucose,  as  seen  in  the  crust  of  bread. 

Making  bread  light.  One  important  quality  of  good 
bread  and  similar  foods  is  that  they  shall  be  light  and  porous. 
This  is  brought  about  by  mixing  some  gas  with  the  dough ; 
for  as  the  dough  is  cooked  these  gases  escape  and  leave  the 
bread  porous.  Sometimes  this  result  is  produced  by  me- 
chanically forcing  air  into  the  dough  by  beating.  Eggs  are 
sometimes  added  to  render  the  dough  more  capable  of  hold- 
ing the  air.  But  usually  something  is  put  with  the  dough 
to  produce  a  gas,  which  rises  through  it  and  makes  it  porous. 
Gas  is  produced  in  dough  by  using  baking  powder  or  yeast. 
In  both  cases  the  same  gas  is  produced,  carbon  dioxid. 

A  baking  powder  is  a  mixture  of  two  compounds  of  such 
a  nature  that  when  water  is  added  the  two  chemicals  act 
on  each  other  and  carbon  dioxid  is  formed.  One  of  these 
compounds  is  usually  baking  soda,  the  other  may  be  cream 
of  tartar,  phosphate,  or  alum.  With  these  a  little  starch  is 
usually  mixed  to  prevent  the  powder  from  becoming  moist. 
In  place  of  baking  powder,  soda  and  sour  milk  may  be  used. 

Yeast  is  also  used  to  make  bread  light.  Yeast  is  a  very 
small  plant ;  a  single  one  is  too  small  to  be  seen  by  the  eye 
without  the  aid  of  a  microscope.  As  a  result  of  the  action 
of  the  yeast  on  the  dough,  carbon  dioxid  is  formed  and  acts 
in  the  same  way  as  that  formed  by  baking  powders  in  making 
the  bread  light.  At  the  same  time  alcohol  is  formed,  but 
in  the  oven  this  passes  off  from  the  bread.  When  war 
breads  were  being  made  by  the  use  of  substitutes  for  wheat, 
it  was  frequently  found  that  the  bread  was  heavy  and  un- 


TOO  SCIENCE  OF  HOME  AND   COMMUNITY 

palatable.  Wheat  contains  a  sticky  substance  called  gluten, 
which  keeps  the  dough  porous  after  the  gases  pass  through 
it.  Barley  and  other  wheat  substitutes  do  not  contain  this 
gluten,  and  so  it  is  necessary  to  mix  a  certain  amount  of 
wheat  with  the  other  flours  in  order  to  furnish  enough  gluten 
to  make  a  light  bread. 


LABORATORY  EXERCISE  12 

Purpose.     To  study  the  action  of  baking  powder  and  yeast. 

Materials.  Baking  powder,  baking  soda,  cream  of  tartar, 
and  vinegar. 

Directions,  i.  Mix  dry  baking  soda  and  cream  of  tartar. 
Add  hot  water  and  note  what  happens.  Add  vinegar  to  baking 
soda.  Put  a  little  baking  powder  into  water  and  note  what 
happens.  Dissolve  baking  soda  and  cream  of  tartar  separately 
in  cold  water,  then  pour  one  into  the  other.  Try  again,  using 
hot  water,  and  note  the  difference. 

2.  Make  a  paste  of  flour  and  water.     Mix  with  this  a  small 
piece  of  yeast  cake.     Allow  to  stand  for  a  while  in  a  warm  place 
and  notice  what  happens. 

3.  Put  in  each  of  two  test  tubes  or  small  bottles  a  teaspoonful 
of  molasses  and  ten  of  water.     Mix  a  small  piece  of  yeast  cake 
with  water  and  add  a  half  to  each  bottle.     Place  one  in  a  cool 
place,  as  in  an  ice  chest,  and  the  other  in  a  warm  place.     At 
the  end  of  a  day  notice  any  difference  in  the  two. 

Methods  of  cooking.  Water  is  an  essential  factor  in  cook- 
ing. Many  foods  are  cooked  in  boiling  water.  This  in- 
sures an  even  temperature  as  water  always  boils  at  the  same 
temperature,  212  degrees,  with  slight  variations  due  to  the 
atmospheric  pressure.  In  the  double  boiler  the  outer  dish 
holds  boiling  water  and  the  inner  dish  the  food  to  be  cooked. 
So  long  as  the  outer  dish  contains  water  the  food  will  not 
burn.  Sometimes,  as  in  stewing,  foods  are  cooked  in  water 
which  is  kept  just  below  the  boiling  point. 


THE  SCIENCE  OF  THE   KITCHEN 

In  cooking  meats,  if  it  is  desired  to  keep  the  vuiees 
the  cut,  the  piece  is  put  directly  into  boiling  water",  which' 
coagulates  the  outside  and  so  forms  a  coating  that  retains 
the  juices  inside.  If  it  is  desired  to  extract  the  juices  from 
the  meats,  as  in  soups,  the  meat  is  first  put  into  cold  water 
and  heated  gradually,  and  thus  many  of  the  juices  dissolve 
in  the  water. 

Some  foods  are  cooked  in  hot  fat,  since  fat  can  be  heated 
to  a  temperature  much  higher  than  that  of  boiling  water. 
It  should  be  so  hot  that  when  the  food  is  placed  in  it,  the 
outside  is  heated  quickly,  forming  a  coating  which  prevents 
the  fat  from  entering  the  inside.  When  the  fat  mixes  with 
all  portions  of  a  food,  a  mass  is  formed  which  is  difficult  to 
digest. 

It  is  seen  that  these  various  methods  of  cooking  involve 
different  temperatures.  In  stewing,  foods  are  cooked  at  a 
temperature  below  212  degrees ;  in  boiling  water,  at  a  tem- 
perature of  212  degrees ;  in  hot  fat,  at  a  temperature  higher 
than  this  ;  and  in  baking,  at  a  still  higher  temperature. 

Early  methods  of  cooking.  It  is  interesting  to  note  the 
changes  that  have  occurred  in  the  methods  of  cooking  since 
the  very  earliest  times.  At  first,  cooking  was  carried  on 
over  the  open  fire  by  broiling,  or  by  roasting  in  hot  ashes. 
Later  on,  crude  kinds  of  kettles  were  suspended  over  the 
fire  and  the  food  was  cooked  by  boiling  or  stewing  in  these. 
Then  the  open  fireplace  indoors  was  used,  and  movable 
ovens,  open  at  one  side,  were  placed  in  front  of  it.  Machines 
were  used  to  turn  meats  which  were  roasted  in  front  of  open 
fires.  Then  various  kinds  of  closed  ovens  were  made. 
Even  within  the  history  of  our  own  country,  open  fireplaces 
and  brick  ovens  were  the  common  means  of  cooking.  In 
more  recent  times  have  appeared  stoves  and  the  gas  range ; 
and  now  cooking  is  being  done  by  electricity.  In  the  future, 
improvements  will  doubtless  be  made  along  this  line,  and 
electricity  may  be  made  so  cheap  that  it  can  be  commonly 


I0'2 


SCIENCE:  OF  HOME  AND  COMMUNITY 


.doing  away  with  the  dust  and  incon- 
venience of  coal  and  wood  stoves. 

Fuels  used  in  cooking.  One  of  the  most  common  means 
of  cooking  is  the  wood  or  coal  range.  This  is  so  constructed 
that  the  heated  gases  are  forced  around  the  oven  before 
escaping  up  the  chimney.  Gas  ranges  are  very  widely  used 
in  towns  and  cities.  The  heat  can  be  started,  controlled, 


Air  infers 


FIG.  31. —  A  kitchen  range. 

and  shut  off  at  will,  and  the  gas  range  is  especially  advan- 
tageous during  warm  weather.  The  burners  are  so  arranged 
as  to  mix  air  with  the  gas,  thus  producing  a  complete  burn- 
ing, which  gives  a  very  hot,  blue  flame.  Usually  these  burners 
are  adjustable,  so  that  the  proper  amount  of  air  may  be 
admitted  to  give  the  hottest  flame. 

LABORATORY  EXERCISE  13 

Purpose.     To  study  the  working  of  a-  Bunsen  burner. 
Directions.     The  burners  on  a  gas  range  work  on  the  same 
principle  as  the  Bunsen  burner.     Take  a  burner  apart,  noting 


THE  SCIENCE  OF  THE   KITCHEN 


103 


the  various  pieces.  Put  it  together  and  light  it.  Cover  the 
air  holes  completely  and  then  leave  them  wide  open.  What 
difference  does  it  make  in  the  flame  ?  Cover  the  hole  partially. 
How  should  the  burners  on  a  gas  range  be  regulated  ? 


1                          Nonconducting      ]A%0ter/o/                \ 

v  — 

Pai/ 

7     V 

Pait 

7     V 

7 
Pait 

Nonconducting    Material 

_r                ~u 

FIG.  32.  —  Fireless  cooker. 


Fireless  cooker.  The  fireless  cooker  is  another  device 
for  cooking.  It  consists  of  a  box  with  a  tightly  fitting 
cover,  in  which  are  placed  several  receptacles  separated 
by  some  material  which  conducts  heat  slowly,  such  as 
hay  or  excelsior.  The  foods  to  be  cooked  are  first  brought 
to  boiling  on  a  stove,  then 
placed  in  these  compart- 
ments and  tightly  cov- 
ered. As  there  is  little 
opportunity  for  the  heat 
to  escape,  the  foods  con- 
tinue to  cook,  and  if  suffi- 
cient time  be  allowed,  they  are  cooked  enough  for  eating. 
Pies  and  bread  may  be  baked  and  meats  roasted.  For  this 
purpose  heavy  plates  are  heated  and  placed  in  the  bottom  of. 
the  compartment  and  the  food  placed  on  these.  If  one  has 
access  to  a  gas  range  or  a  kerosene  stove  by  which  water 
can  be  quickly  heated,  the  fireless  cooker  has  two  great 
advantages,  comfort  during  the  warm  weather,  and  the 
saving  of  fuel.  It  is  claimed  also  that  food  cooked  slowly 
and  for  a  long  time  is  more  palatable  than  when  cooked  by 
the  ordinary  method. 

Thermos  bottle.  The  thermos  bottle,  in  which,  liquids 
may  be  kept  either  hot  or  cold  for  a  long  time,  Js  made 
on  somewhat  the  same  principle.  It  is  virtually  two  Bot- 
tles, one  inside  the  other  separated  by  a  vacuum,,  through 
which  heat  cannot  pass  readily  in  either  direction.  The 
outer  surface  is  made  of  a  bright,  smooth  material  which 
reflects  the  heat  rays  instead  of  allowing  them/  to  pass 
through. 


104  SCIENCE  OF  HOME  AND   COMMUNITY 

Refrigerator.  In  order  to  keep  foods  from  decaying  in 
warm  weather,  the  refrigerator  is  now  widely  used.  The 
bacteria  which  cause  decay  do  not  thrive  at  low  temperatures ; 
hence  food  may  be  kept  for  some  time  in  refrigerators. 
Melting  ice  remains  at  a  temperature  of  3  2  degrees  till  all  is 
melted.  The  air  around  the  ice  is  cooled  and  being  heavier 


FIG.  33.  —  Circulation  of  air  in  a  refrigerator. 

sinks,  and  the  warm  air  in  the  refrigerator  comes  in  to  take 
its  place.  Thus  there  is  a  circulation  of  air  in  the  refrigerator 
similar  to  that  which  takes  place  in  a  room  heated  by  hot  air. 
The  walls  of  the  refrigerator  are  made  of  materials  which  do 
not  conduct  heat  easily  from  the  outside,  and  air  spaces  are 
usually  left  in  the  walls,  as  air  is  a  poor  conductor  of  heat. 
Ice  cream  freezer.  The  freezing  of  cream  and  other 
liquids  in  the  preparation  of  desserts  is  accomplished  in  an 
ice  cream  freezer.  A  freezing  mixture  surrounds  the  vessel 


THE  SCIENCE  OF  THE  KITCHEN  105 

that  contains  the  substance  that  is  to  be  frozen.  It  consists 
of  ice  and  salt,  about  three  parts  of  ice  to  one  of  salt.  Salt 
has  so  great  an  affinity  for  water  that  when  it  is  placed  in 
contact  with  ice  it  causes  the  ice  to  melt.  It  requires  heat 
to  melt  ice,  and  thus  heat  is  taken  from  the  surrounding 
bodies.  A  temperature  may  be  obtained  as  low  as  25  or 
30  degrees  below  the  freezing  point,  that  is,  almost  down  to 
zero  Fahrenheit.  The  brine  formed  does  not  freeze  because 
its  freezing  point  is  much  lower  than  that  of  pure  water. 

LABORATORY  EXERCISE  14 

Purpose.  To  study  the  principles  involved  in  freezing  ice 
cream. 

Materials.  Salt,  ice,  tumbler,  thermometer,  test  tube,  tin 
cup. 

Directions,  i.  Put  a  mixture  of  salt  and  crushed  ice  in  a 
tumbler.  Put  in  this  the  bulb  of  a  thermometer  and  record  the 
temperature.  Try  different  proportions  of  ice  and  salt  and  find 
which  gives  the  lowest  temperature. 

2.  Put  a  test  tube  containing  water  into  the  mixture  of  ice 
and  salt. 

3.  Fill  a  tin  cup  with  snow.     Place  the  cup  on  a  board 
covered  with  a  layer  of  water.     Stir  some  salt  into  the  snow. 
What  happens  to  the  water  on  the  board  and  bottom  of  the 
cup?     Why? 

Causes  of  decay  of  foods.  One  common  problem  in  the 
home  is  to  keep  foods  from  decaying.  The  decay  of  foods 
is  caused  chiefly  by  two  kinds  of  small  plants,  molds  and 
bacteria.  Molds  may  be  seen  with  the  naked  eye  as  thread- 
like plants  growing  upon  various  kinds  of  food.  On  these 
threads  appear  little  stalks,  each  bearing  a  ball.  These  are 
filled  with  a  powder  called  spores,  which  scatter  and  grow 
into  new  plants.  These  molds  have  no  green  coloring  matter 
and  so  cannot  make  their  own  food  like  ordinary  plants, 
but  must  live  on  food  already  made  by  other  means. 


106  SCIENCE  OF  HOME  AND   COMMUNITY 

Bacteria  are  the  smallest  plants  known  and  can  be  seen 
only  with  a  microscope.  They  multiply  very  rapidly,  so 
that  a  few  may  develop  in  a  short  time  into  an  enormous 
number.  Both  molds  and  bacteria  require  moisture  and 
warmth  in  order  to  grow ;  therefore  very  common  means  of 
preserving  foods  are  drying  and  cold  storage. 

DEMONSTRATION  12 

Purpose.  To  study  the  activities  of  bacteria  and  some  means 
of  controlling  them. 

Materials.  Test  tubes,  raw  meat,  beans,  boiled  potato, 
white  of  egg,  salt,  vinegar,  formalin. 

Directions.     I.    The  action  of  bacteria  in  causing  decay. 

a.  Place  in  a  test  tube  a  small  piece  of  raw  meat ;  half  cover 
with,  water.     Set  in  a  warm  place  for  two  or  three  days.     Note 
the  appearance  of  both   meat   and  water.     This  change  has 
been  caused  by  bacteria. 

b.  With  a  knife  heated  in  a  flame,  cut  a  boiled  potato  in  two. 
parts.     On  one  half  of  the  potato  put  some  dust ;  leave  the 
other  half  untouched.     Cover  them  both  and  allow  them  to 
stand  for  several  days.     Note  any  difference. 

2.  Effect  of  drying  on  their  activities. 

In  one  tube  place  a  bean,  in  another  a  bean  half  covered 
with  water.  Allow  them  to  stand  for  a  week  and  note  any 
difference  between  the  two. 

3.  Effect  of  freezing  and  boiling. 

Put  a  small  piece  of  raw  meat  in  each  of  three  test  tubes ; 
nearly  cover  with  warm  water.  Boil  the  water  in  one  tube. 
Plug  all  three  tubes  with  cotton  batting.  Place  one  of  the  tubes 
that  has  not  been  heated  outdoors  where  it  will  freeze,  and  keep 
the  other -in  the  schoolroom  by  the  side  of  the  one  that  has. 
been  heated.  On  the  next  day  bring  in  the  tube  from  out- 
doors and  allow  all  three  tubes  to  stand  in  the  schoolroom  for 
several  days.  Note  any  differences.  What  is  shown  about 
the  effect  of  high  and  low  temperature  on  the  growth  of 
bacteria? 


THE  SCIENCE  OF  THE  KITCHEN  107 

4.    Effects  of  disinfectants. 

Mix  the  white  of  an  egg  with  about  ten  times  its  bulk  of 
water.  Pour  some  of  this  into  each  of  five  test  tubes.  Allow 
the  first  tube  to  remain  as  it  is ;  to  the  second  add  a  little  salt, 
to  the  third  a  little  sugar,  to  the  fourth  some  vinegar,  and  to 
the  fifth  three  drops  of  formalin.  Allow  to  stand  side  by  side 
for  several  days  and  note  any  differences  in  the  effect  of  the 
substances  in  preventing  decay. 

Preserving  foods.  Many  methods  of  keeping  foods  for 
long  periods  of  time  are  used ;  among  the  more  common  are 
drying,  smoking,  the  use  of  preservatives,  and  canning. 
Drying  was  one  of  the  earliest  methods  used  and  is  quite 
common.  Bacteria  and  molds  that  cause  decay  require 
a  certain  amount  of  moisture  in  order  to  live  and  by  drying 
foods  the  amount  of  water  may  be  reduced  to  such  a  limit 
that  these  forms  cannot  exist.  Many  foods  are  already 
dried  as  we  harvest  them,  such  as  the  various  kinds  of  grains, 
peas,  beans,  and  corn ;  and  the  food  obtained  from  these 
by  grinding,  such  as  flour  and  meal,  can  be  safely  kept.  In 
other  cases  artificial  drying  is  used.  For  some  uses  even 
milk  is  evaporated  and  reduced  to  a  dry  powder  that  may 
be  kept  for  a  long  time. 

Drying  fruits  and  vegetables.  Many  kinds  of  vegetables 
and  fruits  can  be  easily  dried  in  the  home.  This  gives  an 
opportunity  to  save  many  vegetables  that  are  commonly 
wasted,  either  because  they  are  allowed  to  go  to  waste  in 
the  garden  or  are  left  over  while  preparing  meals. 

The  general  principle  involved  in  drying  is  that  enough 
water  is  removed  by  evaporation  so  that  bacteria  and  molds 
cannot  live  on  trie  product,  and  it  can  therefore  be  stored 
and  kept.  The  food  to  be  dried  is  first  cut  into  thin  slices, 
or  in  the  case  of  corn  the  kernels  are  cut  from  the  cob. 
These  may  be  dried  in  three  ways :  in  the  sun,  over  a  stove 
or  other  source  of  artificial  heat,  or  before  an  electric  fan. 
For  holding  the  substances  shallow  trays  of  any  convenient 


108  SCIENCE  OF  HOME  AND   COMMUNITY 

size  may  be  used.  The  bottom  should  be  porous  so  as  to 
allow  a  free  circulation  of  air.  For  this  purpose  laths  may 
be  used  with  spaces  between  them,  or  the  bottom  of  the  tray 
may  be  covered  with  a  small-mesh,  galvanized  wire  netting. 
Sun  drying  is  the  simplest  but  requires  the  longest  time, 
varying  from  two  to  three  days  according  to  the  weather. 
The  food  should  be  protected  from  insects  and  dust.  When 
dried  over  the  stove,  the  process  may  be  finished  in  from  two 
to  five  hours.  The  temperature  should  not  be  allowed  to  go 

above  140  or  150  degrees. 
Instead  of  using  heat,  a 
motion  of  air  may  be  em- 
ployed to  hasten  evapo- 
ration. A  number  of 
trays  may  be  put  one  on 
the  other  and  an  electric 
fan  operated  in  such  a 
way  as  to  force  a  current 
of  air  to  pass  over  them. 
Sometimes  insects  lay 

their  eggs  on  the  drying 
FIG.  34.  —  Home-made  drier.  •*      fa 

substances,  especially  if 

the  drying  be  done  in  the  sun,  and  these  eggs  may  hatch 
later  and  the  larvae  eat  the  food.  To  avoid  this  difficulty, 
the  product  may  be  heated  for  a  short  time  in  an  oven  at  a 
temperature  of  about  140  degrees.  This  kills  the  eggs. 

The  dried  products  should  be  stored  in  receptacles  that 
will  protect  them  from  insects,  mice,  and  rats.  Stout  paper 
bags  and  pasteboard  boxes  with  tight  covers  serve  the  pur- 
pose well.  The  products  must  be  protected  from  moisture 
and  they  will  keep  best  in  a  cool,  dry,  well-ventilated  place. 

Where  it  is  desired  to  use  the  dried  products,  they  are 
soaked  for  several  hours  in  water  so  as  to  restore  the  amount 
that  was  lost  by  evaporation.  They  are  then  cooked  in 
about  the  same  way  as  fresh  fruits  and  vegetables. 


THE  SCIENCE  OF  THE  KITCHEN  109 

HOME  PROJECT  12 

Purpose.     To  dry  fruits  and  vegetables  at  home. 

Directions.  Send  to  the  Department  of  Agriculture,  Wash- 
ington, D.  C.,  for  Farmers'  Bulletin  841  on  Drying  Fruits  and 
Vegetables  in  the  Home.  Dry  some  fruits  or  vegetables  at  home, 
following  the  directions  given  in  this  bulletin. 

Preservatives.  Some  foods  are  preserved  by  the  use  of 
salt  or  sugar.  Oftentimes  preservatives  are  used  in  con- 
nection with  the  process  of  drying,  —  salt  with  meats,  and 
sugar  with  fruits  and  berries,  such  as  raisins  and  prunes. 
Smoking  of  meats  such  as  hams  is  often  accompanied  by 
two  other  processes,  drying  and  salting.  Another  harmless 
preservative  that  may  be  used  is  vinegar,  the  acid  quality 
of  which  prevents  the  growth  of  bacteria  that  produce  decay. 
Sometimes  spices  are  used  to  help  preserve  foods,  as  in  mince 
meat  and  sausages. 

Canning.  One  of  the  most  recent  and  widely  used  methods 
of  preserving  foods  is  canning.  This  is  now  such  an  im- 
portant industry  that  most  of  our  common  fruits  and  vege- 
tables can  be  bought  canned.  Canning  has  proved  a  great 
blessing  to  mankind,  since  foods  which  keep  for  only  a  short 
time  in  the  fresh  state  can  now  be  obtained  at  any  season  of 
the  year.  It  is  also  a  means  of  economy  in  the  home.  Vege- 
tables can  be  raised  in  the  garden  and  then  canned  for  winter 
use.  This  may  be  done  at  slight  cost  and  one  is  sure  of  the 
quality  of  the  products  canned. 

The  decay  of  fruits  and  vegetables  is  due  to  the  action  of 
small  plants :  yeasts,  molds,  and  bacteria.  In  canning,  two 
principles  are  involved :  first,  all  these  plants  present  in  the 
fruits  and  jars  must  be  killed :  and  second,  the  cans  must  be 
sealed  in  such  a  way  tnat  no  otners  can  enter. 

Killing  the  bacteria.  The  most  difficult  plants  to  kill  are 
bacteria.  The  method  usually  employed  in  the  home  to 


110  SCIENCE  OF  HOME  AND   COMMUNITY 

kill  these  bacteria  is  to  heat  the  jars  at  the  temperature  of 
boiling  water  for  a  period  varying  from  fifteen  minutes  to 
three  hours,  depending  on  the  product  to  be  canned.  In 
addition  to  the  active  forms  in  which  bacteria  are  generally 
found,  some  exist  in  a  dormant  state,  known  as  spores. 
The  active  form  is  easily  killed  by  a  short  boiling,  but  in 
order  to  kill  the  spores,  a  longer  boiling  is  necessary.  Fruits 
are  easily  canned ;  vegetables  require  more  care.  Lack  of 
success  in  canning  vegetables  is  often  due  to  failure  to  boil 
long  enough  to  kill  these  spores. 

Cold-pack  method  of  canning.  The  process  of  canning 
has  now  been  made  so  simple  that  it  can  be  carried  on  in  the 
home  with  inexpensive  apparatus.  The  first  steps  are  the 
preparation  of  the  products  to  be  canned  and  the  cleaning 
of  the  containers.  It  is  better  to  can  the  products  within 
a  few  hours  after  they  are  picked.  For  home  use  glass  jars 
are  best.  The  jars  should  be  thoroughly  cleaned  and  kept 
in  a  dish  of  hot  water. 

In  the  cold-pack  method,  there  are  five  steps  :  (i)  blanch- 
ing, (2)  cold  dipping,  (3)  packing,  (4)  processing,  and  (5)  seal- 
ing. Blanching  consists  in  putting  the  products  into  boiling 
water  and  allowing  them  to  remain  for  a  few  minutes.  This 
time  varies  from  one  to  fifteen  minutes,  depending  on  the 
kind  of  product.  The  purpose  of  blanching  in  some  cases  is 
to  loosen  the  skins,  as  with  tomatoes,  in  other  cases  to  reduce 
the  bulk  of  the  vegetable.  The  products  may  be  placed  in 
a  piece  of  cheesecloth  or  a  wrire  basket  made  for  the  purpose. 
Blanching  is  omitted  in  canning  berries  and  soft  fruits. 

The  cold-dip  serves  three  purposes :  (i)  to  harden  the 
pulp  under  the  skin  so  that  the  skin  can  be  removed,  (2)  to 
set  the  coloring  matter,  and  (3)  to  make  it  easier  to  handle 
the  products  in  packing. 

The  products  are  then  packed  in  hot  jars.  Sirups  are 
added  to  fruits  and  hot  water  to  vegetables.  For  seasoning, 
a  level  teaspoonful  of  salt  is  added  to  each  quart  of  vegetables. 


FIG.  35.  —  Steps  in  canning. 


112 


SCIENCE  OF  HOME  AND   COMMUNITY 


The  covers  are  put  on  and  partially  closed  and  the  jars  are 
then  placed  in  some  vessel  for  processing.  This  consists  in 
heating  the  jars  so  as  to  kill  bacteria.  The  time  depends  on  the 
kind  of  product  and  the  temperature.  The  simplest  device  for 
home  use  is  the  hot-water  bath  outfit.  This  consists  of  any 
receptacle  in  which  water  can  be  boiled.  It  must  be  deeper 

than  the  height  of  the  jar 
so  that  the  jar  may  be 
completely  covered  with 
water.  Such  utensils  as 
wash  boilers,  lard  pails, 
and  tin  pails  can  be  used. 
Some  kind  of  perforated 
platform  should  be  placed 
on  the  bottom  of  the 
dish  so  as  to  permit  the 
free  circulation  of  water 


FIG.  36.  —  Boiler  for  canning. 


around  and  under  the  jars.  The  water  should  cover  the  tops 
of  the  jars  by  at  least  an  inch.  The  receptacle  should  have 
a  tightly  fitting  cover.  After  the  processing  is  finished  the 
jars  are  removed  and  sealed  tightly  at  once. 

Canning  tomatoes.  As  a  definite  illustration  of  how  the 
method  is  used,  the  following  directions  for  canning  tomatoes 
are  given.  The  tomatoes  are  put  into  a  piece  of  cheesecloth 
and  placed  in  boiling  water  for  one  and  one  half  minutes. 
They  are  then  dipped  into  cold  water  and  the  skins  are  re- 
moved. They  are  then  packed  into  hot  glass  jars  and  a  level 
teaspoonful  of  salt  added  to  a  quart.  The  rubbers  and  caps 
are  put  on,  but  the  cap  is  not  fastened  tight.  The  jar  is 
put  into  hot  water  in  the  wash  boiler  and  allowed  to  remain 
22  minutes  after  the  water  begins  to  boil.  The  jar  is  then 
removed  and  the  cap  fastened  down  securely.  The  jars 
may  be  inverted  to  test  for  any  leaks. 

The  following  table  shows  the  time  of  scalding  and  process- 
ing a  few  common  vegetables  and  fruits. 


THE  SCIENCE  OF  THE  KITCHEN  113 

TIME  TABLE  FOR  BLANCHING  AND  STERILIZING  VEGETABLES  AND  FRUITS 


V  EG  ET  A  BLES 

BLANCHING 

STERILIZING 

Hot  Water 
Outfit 

Steam  Pressure 
5-io  Pounds 

Steam  Pressure 
10-15  Pounds 

(Minutes) 

(Minutes) 

(Minutes) 

(Minutes) 

Asparagus      .     . 

15 

I2O 

60 

40 

Beans,  wax    .     .     . 

5-10 

120 

60 

40 

Beets     

5 

90 

60 

40 

Corn,  sweet    .     .     . 

5 

180 

90 

60 

Peas      

5-10 

1  80 

60 

40 

Spinach     .... 

15 

120 

60 

40 

Squash       .... 

3 

120 

60 

40 

Tomatoes  .... 

I* 

22 

15 

10 

Fruits 

Apples  

I* 

2O 

8 

6 

Cherries     .... 

16 

IO 

5 

Peaches     .... 

1-2 

16 

10 

5 

Pears     

ii 

20 

8 

6 

Plums   

•*•  2 

16 

IO 

5 

Raspberries    .     .     . 

16 

10 

5 

Strawberries  . 

16 

IO 

5 

DEMONSTRATION  13 

Purpose.     To  show  how  to  can  fruits  and  vegetables. 

Directions.  Send  to  the  Division  of  Publication,  U.  S.  De- 
partment of  Agriculture,  Washington,  D.  C.,  for  Farmers* 
Bulletin  839,  "  Home  Canning  by  the  One-Period  Cold-Pack 
Method."  Following  the  directions  there  found,  demonstrate 
before  the  class  the  hot-water  method  of  canning.  Can  at  least 
one  fruit  and  one  vegetable. 


HOME  PROJECT  13 

Purpose.     To  can  fruits  and  vegetables  at  home. 
Secure  the  Bulletin  mentioned  above  and  can  some  fruits 
Of  vegetables  at  your  home. 

i 


114  SCIENCE  OF  HOME  AND   COMMUNITY 

Canning  under  pressure.  Canning  is  also  done  by  steam 
pressure  outfits.  Pressure  raises  the  boiling  point  of  water. 
Under  a  pressure  of  five  pounds,  the  boiling  point  is  228 
degrees,  and  under  a  pressure  of  fifteen  pounds  it  is  250 
degrees.  When  the  products  are  heated  at  these  high  tem- 
peratures they  are  sterilized  in  a  shorter  time.  Under  a 
pressure  of  ten  pounds  only  one  half  to  one  third  as  long  a 
period  is  required  as  with  the  hot-water  outfit.  In  com- 
mercial canneries  these  pressure  outfits  are  used  altogether. 
Small  outfits  for  home  use  can  be  obtained  at  prices  ranging 
from  $15.00  up. 

Chemistry  of  the  kitchen.  The  chemicals  used  in  the 
kitchen  may  be  divided  into  three  classes,  —  acids,  bases, 
and  salts.  Examples  of  acids  are  vinegar  and  the  juices  of 
fruits.  An  acid  has  a  sour  taste  and  turns  blue  litmus  paper 
red.  A  base  has  a  soapy  taste  and  turns  red  litmus  blue. 
Ammonia  and  baking  soda  are  common  examples.  Litmus 
paper  is  used  to  test  for  acids  and  bases.  When  an  acid 
and  base  are  mixed,  it  is  possible  to  reach  a  stage  where  the 
mixture  will  affect  neither  blue  nor  red  litmus  paper.  The 
two  substances  are  said  to  have  neutralized  each  other.  If 
this  solution  be  evaporated,  a  new  substance  will  be  left 
which  is  called  a  salt.  The  particular  kind  of  salt  formed 
depends  on  the  acid  and  the  base  used.  Common  salt  and 
cream  of  tartar  are  examples  of  salts. 

LABORATORY  EXERCISE  15 

Purpose.  To  study  the  action  of  some  substances  used  in 
the  kitchen. 

Materials.  Red  and  blue  litmus  paper,  vinegar,  ammonia, 
limewater,  and  lemon. 

Directions,  i.  Pour  a  little  vinegar  into  a  dish.  Place  in 
it  a  small  strip  of  blue  litmus  paper.  What  change  takes  place  ? 
This  is  the  test  for  an  acid. 

2.    Pour  a  little  ammonia  into  a  dish.     Place  in  it  a  small 


THE  SCIENCE  OF  THE   KITCHEN  115 

strip  of  red  litmus  paper.     What  change  takes  place?     This 
is  a  test  for  a  base. 

3.  Dissolve  some  salt  in  water.     Put  in  this  a  piece  of  red 
and  also  one  of  blue  litmus  paper.     Does  any  change  occur? 
This  is  said  to  be  a  neutral  substance. 

4.  Get  as  many  common  substances  as  you  can  from  the 
kitchen,  such  as  lemon,  orange,  limewater,  sugar,  sour  milk, 
sweet  milk,  buttermilk,  baking  soda,  cream  of  tartar,  baking 
powder,  tomatoes,  an  apple,  any  fresh  fruit,  tea,  coffee,  wash- 
ing soda,  soap,  gold  dust,  wood  ashes,  drinking  water. 

Test  each  one  of  these  with  both  red  and  blue  litmus  paper. 
Test  the  juices  of  the  fruits.  Dissolve  the  powders  in  water. 
After  letting  the  ashes  stand,  pour  through  a  filter  paper. 
Steep  the  tea  and  coffee  in  hot  water.  Place  the  name  of  each 
substance  under  one  of  the  following  headings  in  your  notebook. 


ACID  BASE  NEUTRAL 


Soaps.  Soaps  are  made  by  the  action  of  fats  on  alkalies. 
One  called  caustic  soda  makes  hard  soaps ;  another  called 
caustic  potash  makes  soft  soaps.  The  cleansing  action  of 
soaps  is  due  to  the  fact  that  they  unite  with  the  fatty  sub- 
stances that  hold  the  dirt,  thus  freeing  it,  and  allow  it  to  be 
washed  away.  Washing  soda  also  acts  on  grease,  and  most 
washing  powders  are  mixtures  of  this  soda  and  powdered 
soap. 

Hard  water.  Some  hard  waters  contain  chemicals  in 
solution  which  interfere  with  the  action  of  the  soap,  since 
the  soap  acts  on  these  chemicals  before  uniting  with  the 
grease  around  the  dirt.  Sometimes  this  hardness  can  be 
overcome  by  boiling,  as  when  the  chemical  is  calcium  bi- 
carbonate. This  is  called  temporary  hardness.  Another 
kind,  not  so  easily  remedied,  is  called  permanent  hardness. 
Enough  soap  must  be  used  to  counteract  all  the  chemical 
before  the  soap  will  have  any  cleansing  power ;  and  the  sub- 


Il6  SCIENCE  OF  HOME  AND   COMMUNITY 

stance  thus  formed  is  an  insoluble  chemical  which  further 
interferes  with  the  cleansing.  When  the  drinking  water  is 
hard,  another  supply  of  soft  water  is  frequently  provided  in 
cisterns.  This  water  may  be  pumped  by  hand  or  it  may  be 
made  to  circulate  throughout  the  house  by  means  of  pressure 
tanks  as  already  explained  in  Chapter  IV. 

LABORATORY  EXERCISE  16 

Purpose.     To  learn  the  effect  of  soap  on  hard  water. 

Materials.  Soap,  test  tubes,  calcium  sulfate,  soft  water, 
washing  soda. 

Directions,  i.  To  procure  hard  water,  add  calcium  sulfate 
to  some  water.  Shake  and  filter.  Make  a  soap  solution  by 
heating  a  little  soap  in  soft  water  in  a  test  tube. 

2.  Take  a  little  of  the  hard  water  and  add  to  it  a  measured 
quantity  of  soap   solution.     Shake  the  test  tube.     Take  the 
same  quantity  of  soft  water  and  add  the  same  amount  of  soap 
solution  as  in  the  previous  experiment.     How  do  the  results 
differ  from  those  in  the  previous  experiment?     Why  is  hard 
water  not  satisfactory  for  cleansing  purposes  ? 

3.  To  hard  water,  add  a  little  washing  soda  and  shake  the 
mixture.     Then  add  some  soap  solution.     What  was  the  effect 
of  the  soda  on  the  hard  water  ? 

Removing  stains.  A  stain  may  usually  be  removed  by 
one  of  the  following  methods :  by  dissolving  it ;  by  bleach- 
ing it ;  by  neutralizing  it ;  or  by  absorbing  it.  The  following 
table  shows  what  may  be  used  to  remove  various  stains. 

Kind  of  stain  How  removed 

Grease Dissolved  in  naphtha. 

Fresh  paint Dissolved  in  turpentine. 

Grass Dissolved  in  alcohol. 

Iron  rust   .     .     . Weak  hydrochloric  acid  for  cotton 

or  linen.     Oxalic  acid  for  silk. 

Mildew Bleach  with  Javelle  water. 

Lemonade  .     .  Neutralize  with  ammonia. 


THE  SCIENCE  OF  THE  KITCHEN  117 

Naphtha  works  better  if  placed  in  a  bowl  of  warm  water, 
but  it  is  easily  inflammable  and  forms  dangerous  explosions 
when  brought  near  a  flame,  and  great  care  should  therefore  be 
taken  when  using  it. 

SUPPLEMENTARY    QUESTIONS  FOR   CLASS   DISCUSSION 

1.  In  what  ways  may  cooked  foods  be  more  healthful  than 
uncooked  foods  ? 

2.  How  does  the  action  of  yeast  differ  from  the  action  of 
baking  powders  as  they  are  used  in  baking  bread  ? 

3.  What  are  the  essential  differences  in  the  various  methods 
of  cooking? 

4.  What  advantages  has  the  fireless  cooker? 

5.  In  what  way  is  the  construction  of  a  refrigerator  similar 
to  that  of  a  fireless  cooker  ? 

6.  What  principles  involved  in  hot-air  heating  are  found 
also  in  the  refrigerator  ? 

7.  What  are  the  essential  differences  in  the  various  methods 
of  preserving  foods  ? 

8.  Why  is  hard  water  unsatisfactory  for  cleansing  purposes  ? 

9.  Which  is  the  best  of  the  three  methods  of  drying  foods  ? 
10.    How  does  the  method  of  canning  corn  differ  from  the 

method  of  canning  strawberries  ? 

REFERENCES 

Conn,  Bacteria,  Yeasts,  and  Molds  in  the  Home,  Ginn  and  Co., 
Boston. 

Dodd,  Chemistry  of  the  Household,  American  School  of  Home 
Economics,  Chicago. 

Richards  and  Elliott,  Chemistry  of  Cooking  and  Cleaning,  Whit- 
comb  and  Barrows,  Boston. 


SECTION  B 
ENTERTAINMENT  IN  THE  HOME 

CHAPTER  VII 

MUSICAL  INSTRUMENTS 

What  advantages,  as  a  source  of  pleasure  in 
the  home,  has  each  of  the  following  instruments 
as  compared  with  the  other  two:  phonograph, 
piano,  violin? 

The  phonograph.  Musical  instruments  furnish  a  pleasant 
means  of  home  entertainment.  The  phonograph  is  coming 
to  be  very  widely  used.  Its  advantages  are  evident.  It  does 
not  require  years  of  practice  before  one  can  play  it,  but 
any  one  can  learn  in  a  few  minutes  to  run  the  machine. 
Another  great  advantage  is  the  great  variety  of  selections 
that  can  be  played  upon  it,  representing  all  kinds  of  musical 
instruments  and  combinations  of  human  voices.  Not  only 
can  one  listen  to  a  great  variety  of  music,  but  one  can  hear 
the  very  best,  as  many  of  the  most  famous  singers  and  musi- 
cians are  having  records  made  of  their  performances. 

The  phonograph  is  one  of  the  wonders  of  the  last  twenty- 
five  years.  It  opens  great  possibilities  for  the  future. 
Records  of  the  songs  of  the  great  singers  and  of  the  speeches 
of  great  orators  and  famous  men  may  be  preserved  to  be 
used  long  after  these  people  have  died.  We  may  get  some 
conception  of  what  this  will  mean  if  we  suppose  that  to-day 
we  had  records  of  the  farewell  address  of  Washington  or  bf 

118 


MUSICAL  INSTRUMENTS 


119 


V/bratrng 
fi/aphraym 


the  Gettysburg  address  of  Lincoln,  so  that  we  could  listen 
to  the  voices  of  these  great  men. 

The  phonograph  was  invented  by  Thomas  A.  Edison  in 
1877.  The  first  machine  consisted  of  a  mouthpiece,  across 
which  was  stretched  a  thin  membrane,  to  the  under  surface 
of  which  was  attached  a  sharp  point.  Just  beneath  this 
was  a  cylinder  covered  with  tinfoil,  which  was  rotated  by 
hand.  As  one  spoke  into  the  mouthpiece,  the  membrane 
with  the  point  attached  vibrated  and  the  point  made  inden- 
tations on  the  tinfoil  beneath. 
These  holes  varied  according  to 
the  intensity  of  the  sound.  A 
loud  sound  made  a  relatively 
deep  indentation,  while  a  soft 
sound  made  a  shallow  indenta- 
tion. When  the  record  on  the 
tinfoil  was  finished,  the  point 
on  the  membrane  was  set  back 
on  the  first  part  of  the  groove 
and  the  cylinder  turned  by  hand. 
As  this  point  followed  these  in- 
dentations, it  reproduced  the 
same  vibrations  in  the  membrane 
that  had  made  the  indentations  ; 
and  it  thus  reproduced  the  same 
sounds  that  had  been  spoken  into  it.  The  words  first  spoken 
into  the  mouthpiece  by  Mr.  Edison  and  first  reproduced  by 
the  phonograph  were  the  lines  of  the  poem,  "  Mary  had 
a  little  lamb." 

Since  that  time  a  great  many  improvements  have  been 
made  in  the  phonograph,  but  the  essential  principles  are  the 
same  as  those  used  in  that  first  crude  machine.  The  modern 
phonograph  has  a  device  by  which  the  record  is  kept  rotating. 
This  is  usually  done  by  means  of  a  spring  which  is  wound 
up  by  a  crank  on  the  side  of  the  machine.  It  is  necessary 


To  Sounding 
Chamber 


Soft  Rubber 
Rings 


JVeecf/e  Point 


FIG.  37.  —  Section  of  a  phonograph. 


I2O 


SCIENCE  OF  HOME  AND   COMMUNITY 


that  the  speed  should  be  uniform,  and  this  is  controlled  by 
means  of  a  governor  consisting  of  balls  attached  to  wires 
and  all  rotating  with  the  machine.  The  faster  this  rotates, 
the  more  these  balls  are  thrown  out  by  centrifugal  force; 
and  this  brings  a  disk  on  the  axle  into  contact  with  a  friction 
pad,  so  that  the  speed  is  lessened.  The  speed  may  be  reg- 
ulated by  means  of  a  screw  which  controls  the  position  of 
these  pads. 


To  Resounding 
Chamber 


Wex/ble  Cord 
^D/am  on  d  fb/n  t 

FIG.  38.  —  Section  of  a  phonograph. 

The  tones  are  strengthened  by  means  of  horns.  Some- 
times these  are  visible  and  attached  on  the  outside ;  in  the 
box  form  the  horn  is  hidden  by  the  sides  of  the  box. 

The  making  of  records  is  now  a  large  industry.  Two 
kinds  of  records  are  in  use,  the  cylinder  and  the  disk.  The 
original  records  for  the  cylinder  are  made  in  wax,  from 
which  a  sharp  point  cuts  out  a  thin  shaving,  leaving 
the  record  engraved  on  the  wax.  The  groove  thus  formed 
is  very  shallow,  varying  from  .01  inch  in  depth  to  .001  or 
even  less.  In  order  that  many  copies  of  records  may  be 
made  from  this  original,  it  is  electroplated  with  gold  and 
copper  and  from  this  mold  many  copies  are  made  in 
wax. 


MUSICAL  INSTRUMENTS  121 

For  the  disk  records  a  different  method  is  used.  A  plate 
of  zinc  is  covered  with  a  thin  coating  of  acid-proof  fat.  The 
stylus  is  arranged  to  work  from  side  to  side  and  traces  a  line 
through  this  fat.  This  is  treated  with  acid,  which  etches 
out  the  line  followed  by  the  stylus.  A  mold  is  made  by 
electrotyping,  and  from  this  many  copies  may  be  made  on 
ebonite  plates. 

Although  the  use  of  the  phonograph  in  the  home  as  a 
source  of  enjoyment  is  the  most  common  use  now  made,  it 
is  being  used  for  other  practical  purposes,  and  will  doubtless 
be  so  used  even  more  in  the  future,  as  its  various  applica- 
tions are  perfected.  A  few  of  these  uses  will  be  merely 
mentioned.  The  dictaphone  is  coming  to  be  commonly 
used  by  the  business  man.  He  dictates  his  letters  into  the 
mouthpiece  of  a  recording  instrument.  This  dictation  is 
later  copied  by  a  typist.  In  learning  new  languages,  records 
may  be  used  to  obtain  the  correct  pronunciation.  Mr. 
Edison  has  recently  perfected  an  invention  called  a  telescribe 
by  means  of  which  a  telephone  conversation  may  be  recorded 
on  a  phonographic  cylinder.  A  phonographic  clock  has  been 
devised  which  calls  off  the  hours  and  the  quarter  hours. 

Types  of  musical  instruments.  The  more  common  musi- 
cal instruments  may  be  divided  into  two  groups  :  the  stringed 
instruments,  such  as  the  piano  and  violin,  in  which  the  sound 
is  produced  by  vibrations  of  strings ;  and  the  wind  instru- 
ments, like  the  cornet  and  flute,  in  which  the  sound  is-  pro- 
duced by  vibrations  of  columns  of  air.  There  is  also  a  third 
group  called  the  percussion  instruments  in  which  the  sound 
is  produced  by  the  vibration  of  a  membrane  or  metal  disks, 
as  the  drum  and  cymbals. 

There  are  three  types  of  stringed  instruments :  first,  those 
in  which  the  strings  are  set  in  motion  by  hammers,  as  in  the 
piano ;  second,  those  in  which  the  strings  are  set  in  vibration 
by  bowing,  as  in  the  violin ;  and  third,  those  in  which  the 
strings  are  set  in  vibration  by  the  fingers,  as  in  the  guitar. 


122  SCIENCE  OF  HOME  AND   COMMUNITY 

The  piano.  The  essential  sound-producing  portion  of  the 
piano  consists  of  three  parts :  the  strings,  whose  vibrations 
produce  the  sound,  the  keys  for  setting  the  strings  in  vi- 
bration, and  the  sounding  board.  (See  figure  39.)  The  pur- 
pose of  the  sounding  board  is  to  increase  the  volume  of  the 
sound.  The  volume  of  sound  given  out  by  the  wires  alone 
would  be  too  small  to  make  a  satisfactory  instrument. 

If  one  looks  at  the  strings  on  a  piano,  he  will  find  that  they 
differ  in  three  ways,  —  in  length,  in  size,  and  in  material. 
There  is  another  difference  which  one  cannot  see,  namely, 


FIG.  39.  —  Piano. 

in  tension.  The  different  tones  are  produced  by  various 
combinations  of  these  differences.  Large  strings,  long 
strings,  strings  under  small  tension,  and  heavy  strings  tend 
to  produce  notes  of  low  pitch;  while  small  strings,  short 
strings,  light  strings,  and  strings  under  a  high  tension  tend 
to  produce  notes  of  a  high  pitch.  The  strings  in  a  piano  are 
attached  at  one  end  to  screws  which  may  be  turned;  thus 
the  strain  on  the  strings  may  be  changed.  By  this  means 
a  piano  is  tuned,  as  this  difference  in  tension  affects  the  pitch. 
The  mechanism  which  sets  the  strings  in  vibration  is  a 
system  of  levers  so  arranged  that  by  pressing  down  a  key 
a  hammer  strikes  the  wire.  Usually  several  wires  are  struck 


MUSICAL  INSTRUMENTS  123 

for  each  note.  As  soon  as  the  strings  are  struck,  a  damper 
falls  on  them  to  check  their  vibration  so  as  not  to  interfere 
with  the  succeeding  notes  of  other  strings.  Pressing  the 
loud  pedal  raises  all  these  dampers,  and  thus  increases  the 
loudness  of  the  sound.  The  soft  pedal  may  operate  in 
several  ways:  it  may  press  a  special  damper  against  the 
strings,  it  may  move  the  hammers  nearer  the  strings  so  that 
they  deliver  a  lighter  blow,  or  it  may  allow  the  hammers  to 
strike  only  a  few  of  the  wires  which  are  used  for  the  same 
note. 

The  quality  of  a  tone  given  out  by  a  string  is  affected  by 
the  place  where  the  hammer  strikes  it.  While  the  string 
is  vibrating  as  a  whole,  it  is  at  the  same  time  vibrating  in 
parts,  —  in  halves,  thirds,  fourths,  etc.  Each  of  these 
vibrations  gives  out  a  certain  tone  called  an  overtone,  and 
these  all  combine  to  give  the  note  characteristic  of  a  certain 
string.  A  large  number  of  these  overtones  is  desirable,  as 
they  help  to  make  a  more  pleasing  sound.  The  overtones 
given  off  are  affected  to  some  extent  by  the  place  where  the 
string  is  struck,  as  certain  desirable  overtones  may  be  de- 
stroyed if  the  string  is  struck  at  a  particular  place.  In 
order  to  allow  these  desirable  overtones  to  appear  and  to 
eliminate  the  objectionable  ones,  it  has  been  found  best  to 
have  the  hammer  strike  the  string  at  a  distance  of  from  one 
seventh  to  one  ninth  from  the  end  of  the  wire. 

Other  stringed  instruments.  In  the  violin  the  vibration 
is  produced  by  a  bow  instead  of  a  hammer.  The  pitch  of 
the  strings  in  the  first  place  is  controlled  by  means  of  size, 
materials,  and  tension ;  and  the  violin  is  tuned  by  changing 
the  tension  through  turning  the  keys.  After  the  violin  is 
once  tuned,  the  pitch  of  the  various  notes  is  controlled  by 
varying  the  length  of  the  strings,  by  pressing  the  strings 
against  the  board  with  the  fingers. 

The  method  of  controlling  the  pitch  of  the  notes  in  the 
guitar  and  banjo  is  similar  to  that  in  the  violin.  The  strings 


124  SCIENCE  OF  HOME  AND   COMMUNITY 

are  set  in  vibration  by  the  fingers  instead  of  by  the  bow,  and 
the  sounding  board  of  the  banjo  is  made  of  membrane  in- 
stead of  wood. 

DEMONSTRATION  14 

Purpose.  To  study  some  of  the  principles  underlying  the  use 
of  musical  instruments. 

Apparatus.     Tuning  fork,  sonometer,  violin,  or  guitar. 

Directions,  i.  Set  a  tuning  fork  in  vibration.  Hold  it 
firmly  on  the  box  of  a  violin  or  guitar,  or  on  any  ordinary  box. 
What  difference  is  there  in  the  sound?  What  is  the  use  of 
sounding  boards  ? 

2.  Fasten  on  the  sonometer  two  strings  of  the  same  material 
but    different    diameter.     Place    them    both    under    the    same 
tension.     Strike  them  both  and  note  the  difference  in  pitch. 

3.  Fasten  two  strings  of  the  same  size  and  under  the  same 
tension,  but  of  different  materials.     Strike  them  and  note  the 
difference  in  pitch. 

4.  Use  two  strings  of  the  same  size  and  material.     Put  one 
under  greater  tension  than  the  other.     How  do  they  differ  in 
pitch  ?     Fasten  two  strings  of  the  same  size  and  material  under 
the  same  tension,  but  have  one  wire  about  twice  as  long  as  the 
other.     How  do  they  differ  in  pitch  ? 

5.  Upon  what  factors  do  these  experiments  show  that  the 
pitch  of  a  string  depends  ? 

Wind  instruments.  In  wind  instruments  the  sound  is  pro- 
duced by  the  vibration  of  air  columns.  The  air  may  be  set 
in  vibration  in  several  ways.  In  the  flute  it  is  set  in  vibration 
by  blowing  across  a  hole ;  in  the  clarinet  by  means  of  a 
vibrating  reed ;  and  in  the  cornet  by  means  of  the  vibrating 
lips  of  the  musician.  The  pitch  is  controlled  in  a  variety  of 
ways :  by  changing  the  length  of  the  vibrating  air  column, 
as  in  the  pipe  organ ;  by  blowing  gently  or  hard,  as  in  the 
clarinet ;  by  breathing  fast  or  slow,  as  on  the  cornet ;  or  by 
a  combination  of  several  means,  as  in  the  flute, 


MUSICAL  INSTRUMENTS  125 

SUPPLEMENTARY    QUESTIONS   FOR   CLASS   DISCUSSION 

1 .  What  is  the  most  valuable  use  made  of  the  phonograph  ? 

2.  What  circumstances  might  make  the  phonograph  a  more 
desirable  instrument  to  have  in  the  home  than  a  piano  ? 

3.  If  phonographs  had  been  in  use  for  a  long  time,  so  that 
records  made  50  or  100  years  ago  could  be  obtained  now,  of 
what  use  would  they  be  to  us  ? 

4.  How  is  the  phonograph   able  to  reproduce  the  human 
voice  ? 

5.  How  is  the  pitch  of  the  tones  determined  and  controlled 
in  each  of  the  following  instruments :  piano,  violin,  guitar,  and 
the  various  wind  instruments  ? 

6.  How  do  stringed  instruments  differ  in  the  methods  by 
which  the  strings  are  set  in  motion? 

7.  How  do  wind  instruments  differ  in  the  ways  in  which  the 
air  is  set  into  vibration  ? 

REFERENCES 

Baker,  Boy's  Book  of  Inventions,  Doubleday  Page  and  Co.,  New 

York  City.     Chap.  7  (Phonograph). 
Williams,  How  It  Works,  T.  Nelson  and  Sons,  New  York  City. 

Chaps.  14-16. 


CHAPTER  VIII 
TAKING  PICTURES 

1 .  What  must  one  know  about  a  camera  in  order 
to  take  good  pictures  ? 

2.  What  are  the  different  ways  in  which  films 
may  be  developed  and  prints  made  ? 

History  of  photography.  The  process  of  taking  pictures 
is  now  a  very  simple  matter,  and  any  one  who  wishes  may 
easily  learn  to  take  them.  But  it  has  not  long  been  so  simple. 
Like  other  applications  of  science,  photography  has  gone 
through  many  changes,  starting  from  crude  beginnings  and 
improving  till  it  has  reached  its  present  perfected  state. 
Before  photography  was  possible,  two  inventions  or  dis- 
coveries were  necessary,  first,  the  discovery  that  certain  salts 
are  affected  by  sunlight,  and  second,  the  invention  of  a  device 
by  which  rays  of  light  from  an  object  could  be  focused  to 
form  an  image. 

The  first  photograph  was  made  in  about  1800;  but  the 
man  who  made  it  was  not  able  to  keep  the  picture  after  it 
was  taken,  because  the  sun  blackened  it.  About  twenty 
years  later  a  liquid  was  discovered  which  made  permanent 
the  image  formed  on  the  sensitive  salts  by  exposure  to  light. 
The  first  real  portraits  from  life  were  made  about  18-40  by 
the  daguerreotype  process,  the  picture  being  taken  on  a  metal 
plate.  A  few  years  later  glass  was  used. 

The  first  pictures  on  glass  negatives  were  taken  by  the 
wet-plate  process,  in  which  it  was  necessary  to  have  the  plate 

126 


TAKING  PICTURES 


127 


wet  while  it  was  being  exposed  in  the  camera.  About  1850 
the  dry  plate  was  invented,  and  this  marked  a  great  advance 
in  photography.  The  next  great  improvement  was  the  use 
of  films  in  place  of  glass  for  the  negatives.  Meanwhile  great 
improvements  were  made 
also  in  the  construction 
of  the  camera. 

The  camera.  An  ordi- 
nary focusing  kodak  (see 
figures  40  and  41)  consists 
of  the  following  parts:  a 
light-proof  box,  which  may 
be  drawn  out  in  the  form 
of  a  bellows,  a  lens  in  the 
front  end  of  this,  which 
focuses  an  image  on  a  film 
or  plate  placed  at  the  back 
of  the  box.  In  front  of 
the  lens  is  the  diaphragm 

.  FIG.  40.  —  Folding  camera. 

with  an  adjustable  open- 
ing in  the  center  through  which  the  light  passes,  and  the 
shutter  by  means  of  which  the  exposure  is  made.     On  the 
front  is  a  finder  by  means  of  which  those  objects  that  will 
appear  in  the  picture  may  be  seen. 


DEMONSTRATION  15 

Purpose.     To  show  how  a  camera  forms  images. 

Apparatus.     Convex  lens,  cardboard,  camera. 

Directions.  I.  Hold  a  piece  of  cardboard  on  the  side  of  a 
convex  lens  away  from  a  window.  Move  the  cardboard  back 
and  forth  until  a  distinct  image  of  the  window  is  formed  on  it. 
How  does  the  image  differ  from  the  object? 

2.  Take  a  camera  apart  and  notice  the  use  of  each  part  in 
taking  a  picture. 


128  SCIENCE  OF  HOME  AND   COMMUNITY 

Loading  the  camera.  Cameras  may  be  loaded  in  three 
ways  —  with  glass  plates,  with  a  roll  of  film,  or  with  a  film 
pack.  If  plates  are  used,  the  loading  is  done  in  a  dark  room. 
As  ordinarily  used,  the  film  is  done  up  in  rolls  having  from 
4  to  12  exposures.  This  is  covered  by  a  strip  of  black  paper. 
This  film  may  be  loaded  in  the  daylight.  It  is  mounted  on  a 
spool,  which  is  placed  in  slots  at  one  side  of  the  camera.  It 
is  then  unwound  and  passed  around  the  back  of  the  camera 
to  a  spool  on  the  other  side.  The  camera  is  then  closed  and 
the  spool  is  turned  by  means  of  a  key  on  the  outside  of  the 
camera  till  the  figure  i  on  the  back  of  the  film  is  seen 
through  a  little  window  of  red  glass  on  the  back  of  the 
camera. 


FIG.  41.  —  Principle  of  camera. 

Making  the  exposure.  Three  things  need  to  be  considered 
in  making  the  exposure :  first,  focusing  the  camera ;  second, 
the  size  of  the  stop  to  be  used ;  and  third,  the  time  of  the 
exposure. 

Focusing.  Two  methods  of  focusing  are  used,  one  by 
throwing  the  image  on  a  ground  glass,  and  the  other  by 
judging  the  distance  of  the  object  and  setting  the  lens  of  the 
camera  to  correspond.  In  the  first  method  a  piece  of  ground 
glass  is  set  in  the  back  of  the  camera  in  the  position  to  be 
occupied  by  the  plate  on  which  the  picture  is  to  be  taken. 
The  camera  is  pointed  at  the  object,  the  shutter  is  opened, 
and  a  door  at  the  back  is  opened  to  expose  the  focusing  glass. 
The  operator  throws  a  cloth  over  his  head  to  exclude  the 
light,  and  by  looking  at  the  image  on  the  glass  determines 


TAKING  PICTURES 


129 


when  the  object  is  in  focus ;  meanwhile  he  moves  the  lens 
or  the  back  of  the  camera  back  and  forth  by  means  of  a 
screw,  till  the  image  on  the  glass  shows  distinctly.  This 
image  is  inverted. 

Rising  and  sliding  front.  As  an  aid  in  focusing,  some 
cameras  have  a  rising  and  sliding  front.  By  means  of  a 
screw  and  a  lever  the  lens  may  be  moved  either  up  or  down, 
or  from  side  to  side.  This  enables  one  to  easily  cover  the 
portion  of  the  object  that  is  to  be  included  in  the  picture,  by 
simply  moving  the  lens, 
instead  of  moving  the 
whole  camera  as  would 
otherwise  be  necessary. 

In  the  other  method 
of  focusing,  the  camera 
is  tested  before  leaving 
the  factory,  and  the  po- 
sitions at  which  an  object 
will  be  in  focus  for  certain 
distances  are  marked  on 
the  camera.  The  person 
estimates  the  distance  of 
the  object  and  sets  the 
lens  accordingly.  When 
this  method  of  focusing  is  used,  there  is  attached  to  the 
camera  a  finder,  in  which  appear  the  objects  that  will  show 
in  the  picture.  In  the  box  type  of  kodaks,  there  is  no  focus- 
ing arrangement,  as  the  camera  is  made  so  that  any  object, 
within  ordinary  limits,  will  be  fairly  well  focused. 

Setting  the  diaphragm  and  the  shutter.  After  the  camera  is 
focused,  the  next  steps  are  to  set  the  diaphragm  for  the  size 
of  the  hole,  and  the  shutter  for  the  time  of  exposure.  These 
depend  on  several  factors,  such  as  the  nature  of  the  object 
being  taken,  the  kind  of  day,  and  the  time  of  day.  The 
time  of  exposure  also  depends  on  the  size  of  the  diaphragm. 


FlG.  42.  —  Box  camera. 


130  SCIENCE  OF  HOME  AND   COMMUNITY 

As  the  size  is  decreased,  the  time  of  exposure  must  be  in- 
creased. 

In  what  are  called  snapshots,  the  stop  is  set  for  a  short 
exposure,  from  -^  to  ^  of  a  second.  The  largest  stop  should 
be  in  position.  This  kind  of  exposure  is  best  made  on  bright 
days.  One  motion  of  the  lever  opens  and  closes  the  shutter. 
While  making  the  exposure,  the  camera  should  be  held  level 
and  steady. 

In  what  are  commonly  called  time  exposures,  the  camera 
must  be  placed  on  some  solid  support  like  a  tripod.  The 
stop  may  be  set  at  any  desired  size  and  the  time  of  exposure 
arranged  accordingly.  The  brighter  the  day,  the  smaller 
the  stop  that  may  be  used  and  the  shorter  the  time  of  ex- 
posure in  comparison  with  the  same  objects  on  cloudy  days. 
The  shutter  is  so  set  that  it  can  be  held  open  for  any  desired 
time,  as  determined  by  a  watch. 

The  time  of  these  exposures  usually  varies  from  -J  second 
to  5  seconds,  according  to  the  stop  used  and  the  brightness 
of  the  day.  For  exposures  outdoors  the  small  stop  may  be 
used,  but  a  longer  time  of  exposure  must  be  given.  The 
time  required  for  an  exposure  depends  on  the  time  of  day 
and  on  the  kind  of  day.  Anything  that  causes  a  change  in 
the  intensity  of  light  affects  the  time  of  exposure. 

For  interior  exposures  much  more  time  is  needed  than  for 
outdoor  exposures.  The  time  varies  according  to  the  time 
of  day,  the  number  of  windows  in  the  room,  and  the  color 
of  the  walls  and  hangings. 

Flashlights.  By  means  of  flashlight  powders,  it  is  possible 
to  obtain  pictures  in  the  evening  which  are  nearly  as  good 
as  those  obtained  in  the  day.  The  flash  powders  are  now 
sold  in  the  form  of  sheets,  which  can  be  easily  lighted.  The 
sheet  is  pinned  to  a  piece  of  cardboard  and  should  be  placed 
two  or  three  feet  behind  the  camera  and  two  or  three  feet 
to  one  side.  It  should  be  placed  at  the  same  height,  or  a 
little  higher  than  the  camera.  Just  before  the  picture  is  to 


TAKING  PICTURES  131 

be  taken,  the  shutter  is  opened,  the  largest  stop  being  in 
position,  and  the  flash  paper  is  lighted ;  then  after  the  flash 
the  shutter  is  closed  at  once.  The  time  occupied  by  the  sheet 
in  burning  is  about  one  second. 

Autographic  camera.  In  the  autographic  camera,  there  is 
a  spring  door  on  the  back  covering  a  slit.  After  the  exposure 
of  the  film,  this  spring  door  is  opened  and  one  may  write  on 
the  red  paper  back  of  the  film  any  explanation  of  the  picture 
he  wishes,  using  a  hard-pointed  stylus.  This  is  then  exposed 
to  the  sky  or  to  artificial  lights  for  a  time  varying  from  two 
to  sixty  seconds.  The  door  is  then  closed.  When  the  film 
is  developed,  this  writing  appears  on  the  edge  of  the  picture. 

DEMONSTRATION  16 

Purpose.     To  show  how  to  use  a  camera. 

In  order  to  show  the  various  steps  in  taking  a  picture,  take 
a  group  picture  of  the  class  indoors,  explaining  the  things  that 
must  be  done  in  focusing  the  camera,  setting  the  stop,  and 
making  the  exposure. 

Developing.  After  the  film  is  exposed,  if  it  is  taken  into 
a  dark  room  and  examined  by  a  red  light,  it  will  be  found  to 
look  just  the  same  as  before  exposure.  The  changes  that 
have  occurred  are  not  of  such  a  kind  that  they  can  be  seen 
with  the  eye.  But  there  have  been  some  very  complex 
chemical  changes  produced  by  the  light  that  struck  the  film. 
We  are  all  familiar  with  the  fact  that  light  produces  changes 
in  some  substances.  When  some  kinds  of  cloth  are  exposed 
to  light,  they  fade.  Likewise  some  wall  papers  fade  after  a 
few  years,  as  do  carpets  and  rugs.  Even  an  ordinary  news- 
paper changes  color  when  exposed  to  light  for  a  long  time. 

Some  substances  are  much  more  sensitive  to  light  than 
others.  Compounds  of  silver  with  the  elements  iodin  and 
bromin  are  very  sensitive  to  light,  and  photography  is  based 
on  this  property  of  these  compounds.  The  film  or  glass 


132  SCIENCE  OF  HOME  AND   COMMUNITY 

plate  on  which  the  picture  is  to  be  taken  is  covered  with  a 
thin  coating  of  gelatin  in  which  these  compounds  are  em- 
bedded. When  these  are  exposed  to  light,  chemical  changes 
take  place,  the  amount  of  change  depending  on  the  in- 
tensity of  the  light.  A  white  object  will  produce  more  effect 
on  the  plate  than  a  black  object ;  and  so  by  this  difference 
in  the  action  of  light  from  different  objects,  changes  are 
produced  which  can  later  be  made  visible  and  reproduced 
as  a  picture. 

LABORATORY  EXERCISE  17 

Purpose.     To  show  the  effect  of  light  on  certain  salts  of  silver. 

Materials.  Silver  nitrate,  sodium  chlorid,  and  potassium 
bromid. 

Directions.  Dissolve  a  little  silver  nitrate  in  water  in  a  test 
tube.  Add  an  equal  quantity  of  a  solution  of  sodium  chlorid. 
Filter  and  expose  the  filter  paper  to  sunlight.  What  change 
takes  place  ?  Repeat  the  experiment,  using  potassium  bromid 
in  place  of  sodium  chlorid. 

In  order  to  make  these  changes  in  the  film  visible,  the  film 
is  treated  with  a  certain  chemical  called  a  developer.  This 
developer  acts  on  the  film  in  such  a  way  that  metallic  silver 
is  deposited  in  those  portions  of  the  film  which  have  been 
acted  on  by  the  light.  In  those  parts  that  have  been  most 
acted  upon,  the  largest  amount  of  silver  is  deposited ;  and 
where  there  has  been  the  least  action,  the  least  silver  is 
deposited.  Light  objects,  therefore,  appear  in  the  negative 
as  very  dark  because  there  is  the  most  silver,  and  dark  objects 
very  light,  because  there  is  the  least  silver.  The  plate  at 
this  stage  is  called  a  negative  because  the  shadows  are  re- 
versed. 

Fixing  solution.  If  this  negative  were  taken  out  into  the 
light,  the  silver  salts  which  had  not  been  acted  upon  would 
be  affected  by  the  light,  and  the  negative  would  be  spoiled. 


TAKING  PICTURES  133 

So  the  negative  is  placed  in  a  solution  of  hypo,  which  is 
called  the  fixing  solution.  This  dissolves  the  silver  salts 
which  have  not  been  acted  on.  That  which  remains  on  the 
plate  is  permanent  and  it  may  now  be  taken  into  the  light. 

Developing  in  dark  room.  There  are  two  methods  of 
developing,  the  dark-room  method  and  the  tank  method, 
which  can  be  carried  on  in  daylight.  In  the  dark  room  all 
ordinary  light  must  be  excluded,  but  it  is  found  that  red 
light  has  very  little  effect  on  the  plates,  and  so  a  red  light  is 
provided  by  means  of  which  the  work  can  be  done.  The 
developers  are  usually  bought  in  the  form  of  powders  which 
are  dissolved  in  water  and  poured  into  a  tray.  Two  other 
trays,  one  with  water  and  one  with  hypo,  are  provided. 

The  plate  is  first  immersed  in  water  in  one  of  the  trays 
and  then  placed  in  the  tray  containing  the  developer.  In  a 
short  time  lights  and  shadows  begin  to  appear,  and  then  the 
outline  of  the  objects.  The  stage  of  development  may  be 
watched  by  holding  the  plate  up  to  the  red  light.  Only 
experience  can  tell  one  when  to  stop  the  development.  The 
plate  is  then  placed  in  water  to  remove  the  excess  of  developer. 
Then  it  is  placed  in  hypo  where  it  is  allowed  to  stay  till  the 
salts  that  have  not  been  affected  by  the  light  are  dissolved. 
This  takes  about  fifteen  minutes.  The  plate  is  then  washed 
for  about  an  hour  in  running  water,  or  it  may  be  left  to  soak 
for  five  minutes  each  in  five  changes  of  water.  The  plate 
is  then  taken  out  and  dried. 

Films  may  be  developed  in  the  same  way.  They  may  be 
cut  and  developed  separately  or  the  whole  film  may  be 
developed. 

The  glass  plates  may  be  developed  also  in  the  dark  room 
in  a  tank  in  which  a  number  of  plates  can  be  developed  at 
once.  The  developer  is  poured  into  the  tank,  and  the  plates 
are  put  in  and  allowed  to  remain  a  certain  length  of  time 
according  to  the  strength  of  the  solution  and  its  temperature. 
When  the  time  is  up,  the  developer  is  poured  out,  the  plates 


134 


SCIENCE  OF  HOME  AND   COMMUNITY 


are  washed  with  water,  and  the  hypo  is  added.  In  this 
process  one  does  not  look  at  the  plates  at  all  while  developing. 
Kodak  film  tank.  Films  may  now  be  developed  without  a 
dark  room  by  using  the  kodak  film  tank.  (See  figure  43 .)  This 
consists  of  a  wooden  box,  a  light-proof  apron,  a  transferring 
reel,  and  a  metal  cup.  At  one  end  of  the  box  the  film  is 
fastened,  and  at  the  other  end  is  placed  the  light-proof  apron 
wound  around  an  axle.  Between  the  two  is  the  transferring 
reel.  The  ends  of  both  the  film  and  the  apron  are  fastened 
to  this  reel.  The  cover  is  put  on,  and  then  by  means  of  a 


FiG.  43.  —  Kodak  film  tank. 

handle  on  the  outside  of  the  box  the  film  and  apron  are  wound 
together  on  the  same  reel. 

The  box  is  opened  and  the  reel  is  taken  out  and  put  into 
the  metal  cup,  into  which  the  developing  solution  has  been 
poured.  The  apron  surrounding  the  film  is  perforated  with 
many  small  holes  through  which  the  solution  reaches  the 
film.  It  is  allowed  to  stay  in  the  solution  twenty  minutes. 
If  two  powders  are  used,  it  is  developed  in  ten  minutes. 
The  time  also  varies  according  to  the  temperature,  more 
time  being  required  for  low  temperatures.  The  developer 
is  then  poured  out,  and  the  reel  is  rinsed  several  times  in 
water.  The  reel  is  then  taken  out,  and  the  apron  and  film 
unwound.  The  film  is  separated  from  the  red  paper  and 


TAKING   PICTURES  135 

then  placed  in  the  hypo.  This  may  be  done  in  the  subdued 
light  of  an  ordinary  room.  After  fixing,  it  is  washed  in  water 
and  then  hung  up  to  dry. 

DEMONSTRATION  17 

Purpose.  To  show  how  to  develop  films  in  the  kodak  film 
tank. 

Apparatus.     Kodak  film  tank,  roll  of  exposed  films. 

Directions.  Follow  the  directions  that  come  with  the  tank 
and  develop  a  film  before  the  class.  Pupils  who  have  a  camera 
may  be  invited  to  bring  a  film  to  school  and  develop  it  them- 
selves at  such  time  as  can  conveniently  be  arranged. 

Printing.  As  we  have  already  said,  the  lights  and  shadows 
are  reversed  in  the  negative.  When  a  print,  or  positive,  is 
made  from  this,  we  get  the  lights  and  shadows  in  their  true 
relations.  The  printing  paper  contains  salts  of  silver,  like 
the  negative,  only  they  are  not  so  sensitive  to  light.  This 
paper  is  put  in  contact  with  the  negative  and  exposed  to 
light.  Where  shadows  are  heaviest  on  the  negative,  the 
least  light  will  pass  through,  and  so  under  this  the  positive 
will  be  light ;  while  those  parts  of  the  negative  that  are 
lightest  will  allow  the  most  light  to  pass  through,  and  here 
the  positive  will  be  dark.  Thus  the  conditions  in  the  object 
from  which  the  negative  was  made  are  reproduced. 

There  are  two  types  of  paper,  the  developing  and  the  print- 
ing out.  In  the  first  type,  of  which  velox  is  a  common 
example,  no  image  appears  till  the  paper  is  developed.  In 
the  second  type,  of  which  solio  and  blue  prints  are  examples, 
the  images  appear  during  the  process  of  exposure. 

Developing  paper.  The  action  and  treatment  of  the  de- 
veloping paper  is  much  like  that  of  the  film.  The  paper  is 
placed  in  contact  with  the  negative  and  exposed  to  some 
light,  such  as  gas  or  electricity.  The  time  depends  on  the 
kind  of  paper,  the  light  used,  and  the  distance  the  paper  is 


136  SCIENCE  OF  HOME  AND    COMMUNITY 

held  from  the  light.  For  holding  the  negative  and  paper,  a 
printing  frame  is  used.  The  paper  should  be  handled  in  a 
room  with  subdued  light  and  brought  near  the  source  of 
light  only  at  the  time  of  exposure.  After  exposure  the  paper 
is  placed  in  a  developing  solution  till  the  printing  has  reached 
the  desired  stage,  then  it  is  dipped  in  water  and  placed  in 
hypo,  as  was  done  with  the  negative.  The  paper  is  then 
placed  in  running  water  for  a  few  minutes  or  in  five  or  six 
changes  of  water,  and  is  then  taken  out  and  dried. 

Blue  prints.  The  blue  print  is  an  example  of  a  printing 
out  paper.  It  is  one  of  the  easiest  papers  to  use  because  it 
does  not  require  any  special  chemicals,  water  being  the  only 
thing  needed.  The  chemicals  on  this  paper  are  compounds 
of  iron  instead  of  silver.  This  paper  requires  a  long  time  to 
print.  The  picture  shows  during  the  process  of  exposure, 
and  the  process  may  be  watched  by  opening  one  half  of  the 
back  of  the  printing  frame. 

Mounting.  The  prints  may  be  mounted  by  using  a  dry 
mounting  tissue,  which  comes  in  thin  sheets  and  may  be 
applied  by  pressing  with  a  hot  flatiron.  Or  the  prints  may 
be  soaked  in  water  and  then  mounted  by  using  starch  paste. 

DEMONSTRATION  18 

Purpose.     To  show  how  to  print  pictures. 

Apparatus.  Developed  films,  printing  frame,  blue-print 
paper,  some  developing  paper  like  velox  and  the  necessary 
chemicals  for  using  it. 

Directions,  i.  Make  a  print  with  blue-print  paper,  follow- 
ing the  directions  that  come  with  the  paper. 

2.  Also  make  a  print  from  the  same  negative,  using  a  develop- 
ing paper  and  following  the  directions  that  come  with  it.  Use 
one  of  the  slow  printing  papers.  This  may  be  done  during  the 
daytime  in  the  schoolroom,  if  the  curtains  are  pulled  down  and 
if  the  paper  is  put  into  the  frame  in  a  drawer  or  closet  that  is 
partly  darkened. 


TAKING  PICTURES  137 

3.  Pupils  who  have  a  camera  may  be  invited  to  bring  films 
from  home  and  print  pictures  for  themselves. 

4.  The  method  of  mounting  prints  may  also  be  shown. 

SUPPLEMENTARY    QUESTIONS  FOR   CLASS   DISCUSSION 

1 .  In  what  ways  is  the  camera  similar  to  the  eye  ? 

2.  How  does  the  process  of  taking  pictures  used  to-day  differ 
from  that  used  fifty  years  ago  ? 

3.  What  advantages  has  the  film  over  the  glass  plate? 

4.  What  kind  of  camera  would  you  prefer  to  have  ? 

5.  Which  is  the  better  of  the  two  methods  of  focusing? 

6.  On  what  does  the  time  of  exposure  depend? 

7.  Which  is  the  better  method  of  developing,  the  dark  room 
method  or  the  tank  method  ? 

8.  What  effect  does  the  developer  have  on  the  plate  or  film  ? 

9.  Why  must  a  fixing  solution  be  used? 

iq.  In  what  ways  is  the  treatment  of  a  developing  paper  like 
the  treatment  of  a  film  ? 

ii.  Which  is  the  better  paper  to  use,  the  developing  paper 
or  the  printing  out  paper  ? 

REFERENCE 

How  to  Make  Good  Pictures,  Eastman  Kodak  Co.,  Rochester, 
N.  Y. 


CHAPTER   IX 
HOUSE   PLANTS 

I.    What  plants  are  suitable  for  growing  in  the 
house  and  what  care  do  they  require  ? 

Window  boxes  and  pots.  The  receptacles  used  in  raising 
house  plants  may  be  either  flowerpots  or  window  boxes. 
If  flowerpots  are  used  the  smaller  sizes  should  be  avoided 


FIG.  44.  —  A  window  box. 

as  they  dry  out  quickly.  The  five-  and  six-inch  pots  are  the 
most  convenient  size.  Very  satisfactory  window  boxes  of 
a  size  to  suit  conditions  can  be  made  out  of  boards.  Holes 

138 


HOUSE  PLANTS  139 

should  be  bored  in  the  bottom  to  allow  the  excess  of  water  to 
escape,  which  may  be  collected  in  a  zinc  tray  placed  be- 
neath the  box.  Before  the  soil  is  put  into  the  receptacles, 
pebbles  or  clinkers  or  other  coarse  material  should  be  placed 
in  the  bottom  to  provide  for  good  drainage. 

There  is  a  "  self -watering  flower  box,"  which  is  made  en- 
tirely of  metal  and  has  a  double  bottom.  The  upper  bottom 
is  perforated  by  two  holes,  in  which  are  fitted  sponges,  and 
it  is  pierced  by  a  tube  that  leads  to  the  top  of  the  box. 
Through  this  tube  water  is  poured  into  the  bottom  of  the 
receptacle  and  is  drawn  up  by  the  sponges  and  passed  to  the 
soil.  In  this  way  one  watering  insures  that  the  soil  will  be 
kept  moist  for  a  week.  The  various  receptacles  may  stand 
on  a  table  or  plant  stand  in  front  of  the  window,  or  they 
may  be  placed  on  the  sill  or  on  shelves  or  brackets  in  the 
window. 

Plants  to  select.  In  deciding  on  which  plants  to  select, 
one  should  first  note  the  light  conditions  of  the  room  in 
which  the  plants  are  to  be  kept,  whether  it  is  sunny  or  shaded 
during  most  of  the  day.  If  sunny,  a  great  variety  of  plants 
may  be  grown ;  but  if  shaded,  care  must  be  taken  to  select 
plants  that  do  well  in  such  situations.  Ferns  are  among 
the  best  plants  for  shaded  rooms;  other  plants  that  will 
thrive  fairly  well  in  the  shade  are  asparagus  sprengeri, 
aspidistra,  begonia,  English  ivy,  oxalis,  and  primroses. 
These  will  also  do  well  in  the  sun.  Others  that  are  well 
adapted  for  a  sunny  location  are  geraniums,  heliotropes, 
wandering  Jew,  fuchsia,  and  bulbous  plants.  In  general 
it  may  be  said  that  the  plants  that  thrive  best  in  the  shade 
are  those  that  are  raised  for  their  foliage  rather  than  for  their 
flowers.  Illuminating  gas  interferes  with  the  growth  of 
plants,  so  that  if  this  is  used  in  the  house  the  kinds  of  plants 
that  can  be  successfully  raised  will  be  limited. 

Care  of  the  plants.  The  chief  consideration  in  the  care 
of  the  plants  is  to  supply  them  with  the  right  amount  of 


T40  SCIENCE  OF  HOME  AND   COMMUNITY 

water.     The  soil  should  not  be  allowed  to  become  dry,  nor 
on  the  other  hand  should  it  be  saturated.     One  can  tell  by 


FIG.  45.  —  Window  made  attractive  with  house  plants. 


the  appearance  of  the  soil  and  its  feel  to  the  fingers  when  it 
is  dry  enough  to  need  watering.  When  the  plant  is  watered, 
the  work  should  be  done  thoroughly  until  water  runs  into  the 


HOUSE  PLANTS  141 

drainage  pan  or  saucer.  The  water  that  collects  in  this 
should  be  thrown  away.  No  more  water  should  be  given 
until  the  soil  becomes  dry  on  top. 

During  the  cold  weather,  care  should  be  taken  that  the 
plants  are  not  exposed  to  a  low  temperature. 

As  the  roots  live  in  such  a  small  amount  of  soil,  some 
fertilizer  should  be  added  occasionally.  Different  kinds 
may  be  bought  that  are  specially  designed  for  house  plants. 

Insect  enemies.  The  more  common  insects  that  may 
occasionally  attack  house  plants  are  plant  lice,  mealy  bugs, 
and  scale  insects.  Plant  lice,  either  the  green  or  the  brown 
.species,  are  the  most  common  pests.  One  remedy  is  to 
sprinkle  tobacco  dust  on  the  leaves  while  they  are  moist, 
allow  it  to  remain  a  few  days  and  then  wash  it  off.  The 
mealy  bugs  appear  as  tiny  tufts  of  cotton  on  the  leaves  and 
in  their  axils.  Both  of  these  may  be  removed  with  a  stiff 
brush  or  washed  with  a  solution  of  whale-oil  soap,  or  sprayed 
with  kerosene  emulsion.  The  red  spider  is  a  very  small 
animal  found  with  its  web  on  the  under  side  of  the  leaf. 
It  may  be  removed  by  spraying  with  water. 

HOME  PROJECT  14 

Purpose.     To  beautify  the  home  by  means  of  house  plants. 

Directions.  Talk  the  matter  over  with  your  parents  and  if 
they  are  willing  and  the  conditions  are  favorable,  start  some 
house  plants  in  your  own  home.  Follow  the  directions  given 
in  this  chapter.  Plant  some  bulbs  as  explained  in  the  latter 
part  of  the  chapter. 

SCHOOL  PROJECT  2 

Purpose.  To  make  the  schoolroom  attractive  by  means  of 
house  plants. 

Materials.     Flowerpots,  window  boxes,  house  plants. 

Directions.  Early  in  the  fall  the  class  should  make  plans 
to  keep  some  house  plants  in  the  schoolroom  during  the  year. 


142  SCIENCE  OF  HOME   AND   COMMUNITY 

The  boys  can  make  the  window  boxes,  or  flowerpots  may  be 
used.  Doubtless  plants  will  be  donated  by  various  members 
of  the  class  ;  or  if  not,  the  class  may  plan  some  method  for 
securing  the  needed  plants.  Some  bulbs  should  be  started  as 
explained  in  the  latter  part  of  the  chapter.  The  class  may  be 
divided  into  committees,  each  to  look  after  the  plants  for  a 
certain  period. 

Propagation  of  house  plants.  A  number  of  house  plants 
may  be  raised  by  means  of  soft-wood  cuttings,  which  are 
made  from  the  growing  parts  of  the  stem.  If  only  a  few 

cuttings  are  to  be  raised,  an  ordi- 
nary flowerpot  may  be  used.  If 
a  larger  number  is  desired,  one 
will  need  a  box  six  or  seven  inches 
in  depth  and  as  long  as  desired. 
These  receptacles  should  be  half 
filled  with  clean,  moist  sand,  well 
pressed  down.  To  make  the  cut- 
ting, a  growing  tip  two  to  four 
inches  long  is  cut  just  below  a 
joint.  The  lower  leaves  are  re- 

FIG.  46.  -  Geranium  cutting.  gQ  ^ 


inch  of  free  stem  ;  and  to  reduce  still  more  the  leaf  surface, 
it  is  well  to  cut  off  about  half  of  each  of  the  remaining 
leaves.  An  incision  is  made  in  the  sand  by  means  of  a  knife, 
and  into  this  the  cutting  is  inserted  for  about  an  inch  and 
the  sand  is  pressed  firmly  about  it. 

To  prevent  too  great  evaporation,  a  tumbler  or  pane  of 
glass  is  used  as  a  cover,  leaving  a  little  crack  for  the  entrance 
of  air.  The  sand  should  be  kept  moist  but  not  saturated. 
The  cutting  should  be  left  until  new  leaves  begin  to  form, 
which  with  a  hardy  plant  like  a  geranium,  will  take  about 
three  weeks.  This  is  evidence  that  new  roots  have  formed, 
and  now  the  plant  may  be  transplanted.  Geraniums  and 
wandering  Jew  may  be  easily  raised  in  this  way  and  also 


HOUSE  PLANTS  143 

begonia,  carnation,  chrysanthemum,  coleus,  rose,  and  fuchsia. 
Cuttings  of  the  wandering  Jew  and  of  some  geraniums  may 
be  successfully  started  in  water,  and  then  transplanted  after 
the  roots  have  formed. 

Leaf  cuttings.  The  rex  begonia  may  be  propagated  by 
means  of  leaf  cuttings.  The  leaf  is  cut  into  triangular  pieces, 
each  containing  a  bit  of  the  leaf  stalk.  The  tip  is  inserted 
into  the  sand,  as  with  soft-wood  cuttings,  and  the  same  care 
is  given. 

SCHOOL  PROJECT  3 

Purpose.     To  raise  cuttings  to  take  home. 

Materials.  Window  box,  sand,  piece  of  glass,  cuttings  of 
various  house  plants. 

Directions,  i.  Secure  a  window  box  and  fill  it  two  thirds 
full  of  clean  sand.  Obtain  cuttings  of  the  plants  you  desire 
to  raise.  Plant  these  cuttings  and  care  for  them,  following  the 
directions  already  given  in  the  text.  Members  of  the  class 
should  take  turns  in  caring  for  the  plants. 

2.  When  they  are  ready  for  transplanting,  members  of  the 
class  are  invited  to  bring  flowerpots  from  home.  The  cuttings 
are  transplanted  from  the  window  box  into  the  flowerpots,  which 
are  then  taken  home  by  the  pupils. 

Bulbs  for  indoor  blooming.  Flowers  may  be  easily  ob- 
tained in  the  winter  by  planting  bulbs  in  the  fall.  Roots 
are  formed  in  some  cool,  dark  place  and  the  plants  are  then 
brought  into  the  house,  and  by  means  of  warmth  and  water- 
ing they  are  forced  to  bloom  earlier  than  they  would  have 
done  if  left  outdoors  until  the  warmth  of  spring  started  their 
growth. 

Outfit  needed.  Ordinary  flowerpots  may  be  used  for  hold- 
ing the  bulbs,  or  a  shallow,  wooden  box  with  holes  for  drainage 
may  be  made.  In  the  bottom  of  the  pot  there  should  be 
placed  a  flat  stone  or  piece  of  broken  pot  over  the  hole,  and 
on  this  a  few  more  pieces  of  coarse  material  to  allow  good 


144 


SCIENCE  OF  HOME  AND   COMMUNITY 


drainage.  On  this  a  little  soil  should  be  placed  and  then 
the  bulb,  which  is  covered  with  enough  soil  to  just  conceal 
the  tip.  More  satisfactory  results  will  be  obtained  if  several 
bulbs  of  the  same  kind  are  placed  in  one  pot  about  an  inch 
apart.  Three  bulbs  the  size  of  a  Roman  hyacinth  may 
be  placed  in  a  five-inch  pot,  and  about  six  the  size  of  the 

crocus.  The  pot  should  not  be 
filled  to  the  brim,  as  room  should 
be  left  for  watering. 

Care  of  the  bulbs.  The  pots 
should  then  be  placed  in  a  dark, 
cool  place  and  allowed  to  remain 
until  the  root  system  has  well  de- 
veloped. If  there  is  a  part  of  the 
cellar  not  affected  by  the  furnace 
heat,  the  pots  may  be  placed  there 
and  covered  to  keep  out  the  light. 
They  should  be  watered  occasion- 
ally. The  bulbs  may  be  set  away 
at  any  time  from  the  middle  of 
September  until  the  middle  of  No- 
vember, but  in  general  October  is 
the  best  time. 

On  the  whole  the  simplest  method 
for  the  hardy  bulbs  is  to  put  the 
flowerpots  outdoors  on  boards  and  cover  them  with  leaves 
or  manure  to  exclude  the  light.  If  the  covering  is  well 
moistened,  the  bulbs  will  not  need  any  further  care  until 
they  are  taken  indoors. 

The  first  three  bulbs  given  below  in  the  table  will  not 
stand  freezing  and  so  must  be  kept  at  a  temperature  above 
32  degrees.  The  other  bulbs  will  stand  a  temperature  below 
freezing. 

When  the  plants  are  first  brought  in  they  should  be 
kept  for  a  few  days  in  dim  light  and  at  a  low  temperature 


FIG.  47.  —  Hyacinth  bulb  that 
formed  roots  while  it  was 
in  the  dark. 


HOUSE  PLANTS 


145 


and  then  gradually  brought  into  the  bright  light  and  high 
temperature  of  the  living  room.  In  order  to  secure  a 
continuous  succession  of  bloom,  different  varieties  of 
bulbs  may  be  chosen,  or  the  same  variety  may  be  brought 
in  at  different  times.  The  plants  should  be  kept  well 
watered. 

In  this  table  are  given  some  results  with  a  few  kinds  of 
bulbs  based  on  actual  experience. 


NAME 

TIME  TO  KEEP  IN 
DARK 

TIME  TO  BLOOM 
AFTER  BROUGHT 
TO  LIGHT 

TIME  REMAIN- 
ING IN  BLOOM 

Chinese  Lily      

2    weeks 

5-6  weeks 

3  weeks 

Paper  White  Narcissus   .     . 

5-6    weeks 

5—6  weeks 

3—4  weeks 

White  Roman  Hyacinth 

7-8    weeks 

3-4  weeks 

3-4  weeks 

Double  Roman  Narcissus    . 

8-9    weeks 

4  weeks 

2  weeks 

Grand  Soleil  d'  Or  Narcissus 

8-9    weeks 

6-7  weeks 

3  weeks 

Crocus      

10  weeks 

6-7  weeks 

4—5  weeks 

Dutch  Hyacinth     .... 

ID-  1  1  weeks 

6-7  weeks 

2  weeks 

Von  Sion  Narcissus     . 

11-13  weeks 

4-5  weeks 

2-3  weeks 

Trumpet  Princeps  Narcissus 

15  weeks 

4—5  weeks 

2  weeks 

Princess  Marianne  Tulip     . 

15-17  weeks 

3-4  weeks 

3  weeks 

Growing  bulbs  in  water.  The  Chinese  lily,  Paper  White 
narcissus,  and  the  Roman  hyacinth  may  be  raised  in  water. 
Special  glasses  are  sold  for  this  purpose.  The  water  should 
just  touch  the  bottom  of  the  bulb.  The  glass  should  be  set 
away  in  a  cool,  dark  place  until  the  roots  develop,  when  it 
may  be  brought  into  the  light.  (See  figure  48.) 

These  same  bulbs  may  also  be  grown  in  a  dish  containing 
pebbles  and  water.  The  Chinese  lily  blooms  very  success- 
fully when  treated  in  this  way.  A  shallow  dish  is  half  rilled 
with  pebbles  and  the  bulbs  are  placed  among  the  pebbles 
so  that  they  will  be  partially  supported  by  them.  Water 
is  added  till  it  touches  the  bottom  of  the  bulb.  This  is  kept 
in  a  dark  closet  for  a  week  or  two,  till  the  roots  begin  to  form, 
L 


146 


SCIENCE  OF  HOME  AND   COMMUNITY 


and  then  brought  to  the  light.     Water  should  occasionally 
be  added  so  as  to  keep  the  base  of  the  bulb  wet. 


FiG.  49.  —  Section  of  a  dish  showing  method 
of  planting  bulb  of  Chin:s3  lily. 


FiG.  48.  —  Roman  hyacinth. 


FIG.  50.  —  Chinese  lily. 


SCHOOL  PROJECT  4 

Purpose.  To  supply  the  rooms  in  the  school  with  flowers 
during  the  winter. 

Materials.     Flowerpots,  bulbs. 

Directions.  I.  The  planning  for  providing  the  various 
schoolrooms  with  flowers  during  the  winter  should  begin  in  the 
early  fall.  If  a  good  supply  of  bulbs  cannot  be  secured  in  town, 
send  to  some  reliable  firm  for  a  catalog.  Plans  should  be  made 
regarding  the  kinds  and  number  of  bulbs  to  plant.  The  Chinese 


HOUSE  PLANTS  147 

lily  bulb  should  be  started  as  early  as  it  can  be  obtained  in  the 
fall  so  as  to  secure  the  bloom  before  the  Christmas  vacation. 
The  other  bulbs  may  be  started  any  time  before  November. 
The  first  may  be  brought  in  just  after  the  Christmas  vacation. 

2.  Follow  the  instructions  already  given  in  the  text  in  caring 
for  the  bulbs.     Special  care  should  be  taken  to  see  that  the 
plants  do  not  freeze  between  Friday  and  Monday.     The  re- 
sponsibility for  doing  the  work  may  be  divided  among  the 
different  members  of  the  class. 

3.  The  particular  purpose  for  which  the  flowers  are  to  be 
raised  may  be  changed  to  adapt  it  to  local  conditions.     In 
some  cases  they  might  be  raised  for  the  hospitals. 

HOME  PROJECT  15 

Purpose.     To  raise  a  Chinese  lily  for  a  Christmas  present. 

Materials.     Shallow  glass  dish,  pebbles,  Chinese  lily  bulb. 

Directions.  A  novel  and  very  pleasing  Christmas  present 
may  be  made  for  a  friend  by  starting  a  Chinese  lily  bulb  about 
six  weeks  before  Christmas.  At  the  end  of  that  time  it  will 
be  just  about  ready  to  blossom.  Follow  the  instructions  given 
in  the  last  paragraph  of  the  chapter  preceding  School  Project  4. 

SUPPLEMENTARY    QUESTIONS   FOR   CLASS   DISCUSSION 

1 .  What  things  must  be  taken  into  consideration  in  selecting 
plants  suitable  for  growing  in  the  house  ? 

2.  What  are  some  of  the  difficulties  to  be  met  in  raising  house 
plants  ? 

3.  What  are  the  advantages  of  propagating  house  plants  from 
cuttings  ? 

4.  What  advantages  do  bulbs  have  as  a  means  of  obtaining 
flowers  ? 

5.  Of  how  many  places  can  you  think  where  the  proper  con- 
ditions for  keeping  bulbs  exist  ? 

REFERENCES 

Dorner,  Window  Gardening,  Bobbs  Merrill  Co.,  Indianapolis,  Ind. 
Bailey,  Manual  of  Gardening,  Macmillan  Co.,  New  York  City. 


SECTION  C 
ELECTRICITY  IN  THE  HOME 

CHAPTER  X 
SOME    APPLICATIONS    OF    ELECTRICITY    IN    THE    HOME 

Outside  of  lighting,  which  do  you  consider  the  most 
valuable  use  that  can  be  made  of  electricity  in  the 
home? 

One  very  common  use  now  made  of  electricity  in  the  home 
is  for  lighting,  as  we  have  seen  in  a  previous  chapter.  When 
once  the  electric  current  has  been  brought  into  the  house, 
there  are  many  other  uses  to  which  it  can  be  put.  The  pur- 
pose of  this  chapter  is  to  explain  some  of  the  uses  of  electricity 
in  the  home  besides  lighting.  It  can  be  used  for  cooking, 
for  heating,  and  for  cleaning,  and  motors  may  be  used  to 
run  fans  and  sewing  machines.  At  present  the  cost  of  the 
electric  machines  and  of  the  electricity  to  run  them  is  high, 
but  doubtless  in  the  future  these  will  be  made  cheap 
enough  so  that  many  people  can  afford  to  use  them. 

Cooking  by  electricity.  Electricity  finds  many  applica- 
tions in  cooking.  Among  the  more  common  appliances  are 
the  following :  electric  toaster,  coffee  percolator,  waffle 
iron,  gridiron  for  cooking  griddle  cakes,  broiler  for  cooking 
steaks,  frying  pan,  kettle  for  boiling  water,  and  oven  for 
baking.  Many  of  these  can  be  used  directly  on  the  dining 
table  at  the  time  of  the  meal,  such  as  the  toaster,  coffee 
percolator,  and  egg  boiler.  These  may  be  connected  to  an 

148 


ELECTRICITY  IN   THE   HOME  149 

ordinary  electric  light  socket  by  unscrewing  the  lamp  and 
inserting  a  plug  with  a  wire  fastened  to  it,  or  a  special  socket 
may  be  installed  in  the  side  wall. 

In  these  various  appliances  electricity  is  made  to  produce 
heat.  In  order  to  do  this,  elements  are  used  which  give  off 
heat  without  much  light  and  thus  transfer  the  heat  to  the 
apparatus.  These  elements  are  made  of  substances  which 
are  not  good  conductors  ;  and  when  electricity  passes  through 
them  they  offer  great  resistance  and  so  convert  the  electricity 
into  heat.  Wires  are  very  commonly  used ;  and  the  smaller 
and  longer  the  wire,  the  greater  the  resistance  and  heat. 
Long  coils  of  small  wire  are  wound  in  a  small  compass  and 
placed  near  the  object  to  be  heated.  The  amount  of  heat 
also  depends  on  the  strength  of  the  current.  By  using 
different  combinations  of  lengths  and  diameters,  different 
temperatures  can  be  obtained.  A  wire  of  nickel  alloy  is 
very  frequently  used.  Wires  of  iron  and  german  silver 
have  also  been  tried.  In  some  appliances  these  wires  are 
visible,  as  in  the  toaster;  in  others  they  are  covered, 'as  in 
the  percolator.  In  other  elements,  instead  of  wires,  thin 
coatings  of  certain  metals,  such  as  gold  and  platinum,  which 
have  been  deposited  on  a  piece  of  mica  are  used.  These 
various  elements  are  made  into  the  shapes  which  will  most 
conveniently  fit  the  appliance  for  which  they  are  intended. 

Toaster.  Some  advantages  of  the  electric  toaster  are 
that  it  may  be  kept  on  the  dining  table  and  the  toast  can 
be  kept  hot.  The  heating  element  is  composed  of  a  series 
of  coils  of  wire  exposed  to  view.  In  some  toasters  the  coils 
are  placed  horizontally ;  in  other  toasters  they  are  placed 
vertically. 

Coffee  percolator.  The  top  portion  of  these  percolators 
is  made  on  the  same  principle  as  other  percolators,  but 
at  the  bottom  is  a  heating  element  that  boils  the  water. 
This  lower  part  is  a  disk  stove  over  which  the  upper  part 
fits  closely.  The  heating  element  is  a  long  wire  in  the  form 


150  SCIENCE  OF  HOME  AND   COMMUNITY 

of  a  spiral,  embedded  in  enamel.  This  enamel  is  baked  to 
the  under  side  of  the  top  plate.  It  requires  about  ten 
minutes  to  make  the  coffee,  starting  with  cold  water.  In 
one  form  of  percolator  the  top  may  be  removed  and  the 
bottom  part  be  used  for  boiling  eggs. 

The  small  disk  stoves  for  heating  a  small  quantity  of 
water  for  boiling  eggs,  or  any  other  purpose,  are  made  in 
much  the  same  way  as  the  bottom  part  of  the  coffee  per- 
colator. 

Electric  kettle.  The  electric  kettle  is  a  convenient  device 
for  heating  water.  The  construction  of  the  lower  part  in 
some  kettles  is  similar  to  that  of  the  coffee  percolator.  In 
others  the  heating  element  is  in  the  form  of  a  band  placed 
around  the  outside.  In  still  another  form,  the  heating  unit 
is  in  the  form  of  a  small  cylinder,  which  is  immersed  in  the 
water.  Some  kettles  are  mounted  on  feet  so  that  they  can 
be  placed  on  the  table,  without  heating  the  table  cover. 

Electric  oven.  Many  kinds  of  electric  ovens  have  been 
made.  These  usually  have  two  iron  grids,  one  at  the  top 
and  one  at  the  bottom.  Each  of  these  has  fastened  to  it 
pieces  of  enamel,  in  which  are  embedded  coils  of  wire. 
The  heated  wires  transfer  the  heat  through  the  enamel  to 
the  grid,  and  then  to  the  air  in  the  oven.  These  ovens  have 
two  walls  separated  by  some  substance  which  does  not 
conduct  heat  readily. 

Cleaning  by  electricity.  Electricity  may  be  put  to  many 
house-cleaning  uses.  For  this  purpose  we  find  the  electric 
vacuum  cleaner  for  cleaning  carpets  and  upholstered  articles, 
the  electric  washing  machine  and  wringer  for  washing  clothes, 
the  iron  for  ironing  them,  and  the  dish-washing  machine. 

Electric  vacuum  cleaner.  In  the  electric  vacuum  cleaner 
a  motor  is  arranged  to  run  a  fan,  which  sucks  up  the  dirt 
through  a  nozzle  which  rests  on  the  surface  that  is  to  be 
cleaned.  Particles  of  dust  and  dirt  are  picked  up  and  col- 
lected in  a  bag  attached  to  the  machine.  The  'cleaner  is 


ELECTRICITY  IN  THE  HOME 


Cleaning 


Hose 


Nozzle 


FIG.  51.  — Electric  vacuum  cleaner. 


easily  guided  to  any  part  of  the  room.  It  raises  no  dust  and 
may  be  used  to  clean  not  only  floors,  but  also  furniture, 
books,  walls,  and  draperies. 
Electric  connection  may  be 
made  with  any  lamp  socket. 

Washing  machine.  The 
electric  washing  machine  con- 
sists of  a  tub  in  which  the 
clothes  are  washed,  a  wringer, 
and  a  motor  which  may  be  con- 
nected with  either  the  tub  or 
wringer. 

Electric  iron  (see  figure  52). 
The  value  of  the  electric  iron 
is  widely  appreciated  and  it  is 
in  general  use.  It  maintains 
an  even  temperature;  and  it  is  especially  valuable  during 
the  warm  weather,  as  it  is  much  more  comfortable  to  use 
than  the  old  type  of  iron,  which  required  proximity  of  a  hot 
fire.  The  heating  element  in  some  irons  is  a  coil  of  wire 
wound  over  the  flat  strips  of  mica  laid 
close  to  the  bottom  of  the  iron.  In 
other  irons  the  heating  element  consists 
of  films  of  alloys  of  several  metals  on  a 
mica  base.  Some  irons  have  a  device 
so  that  three  degrees  of  heat  may  be  ob- 
tained, high,  medium,  and  mild.  This  is 
regulated  by  changing  the  position  of  the 
asbestos  plug  at  the  back,  which  comes 
in  contact  with  three  pins  connected  to 
the  heating  elements  in  the  iron. 

Electric  dish-washer.  The  dishes  are  placed  in  a  basket 
on  a  revolving  plate,  and  hot  water  is  sprayed  against  them 
with  such  force  that  they  are  quickly  cleaned.  They  are 
then  rinsed  in  clean  hot  water  and  allowed  to  dry.  The 


152  •    SCIENCE  OF  HOME  AND   COMMUNITY 

power  for  turning  the  dishes  is  furnished  by  a  motor.  The 
water  may  be  heated  either  by  electricity  or  by  a  fire. 

Electricity  for  heating.  One  means  of  heating  is  the 
luminous  radiator.  This  consists  of  a  frame  in  which  vary- 
ing numbers  of  lamps  may  be  screwed.  These  are  usually 
inclosed  in  a  bulb  of  frosted  glass.  The  filaments  in  the 
lamp  give  off  their  heat  by  radiation  to  objects  near.  Such 
a  radiator  may  be  moved  from  one  room  to  another  and 
may  be  used  like  a  fireplace  to  take  the  chill  off  a  room  in 
the  late  fall  and  early  spring. 

Another  form  of  heater  is  the  convector.  The  principle 
involved  here  is  the  same  as  in  appliances  for  cooking. 
Various  forms  of  heating  elements  are  used.  These  heat  the 
air  and  cause  a  circulation,  the  warm  air  rising  and  the  cooler 
air  coming  near  to  be  heated.  The  amount  of  heat  may  be 
controlled  by  means  of  switches.  In  another  'type  of  con- 
vector  the  elements  become  red  hot  and  give  off  a  glow  like 
the  luminous  radiator. 

Electric  fan.  The  electric  fan  is  operated  by  a  motor. 
Its  use  in  summer  for  cooling  purposes  is  well  known,  but 
it  has  other  uses.  It  may  be  used  in  the  winter  to  help  heat 
the  house.  For  this  purpose  it  may  be  placed  in  the  cold-air 
inlet  of  a  hot-air  furnace,  it  may  be  placed  over  a  register, 
or  it  may  be  placed  in  front  of  a  steam  or  hot-water  radiator 
and  a  current  of  air  directed  against  it.  In  each  case  the 
room  is  heated  more  quickly.  Fans  may  also  be  used  in 
drying  fruits  and  vegetables. 

Other  uses  of  the  motor.  Other  uses  of  the  motor  besides 
those  which  have  already  been  mentioned  are  to  run  a  sew- 
ing machine,  turn  an  ice  cream  freezer  or  coffee  grinder,  and 
work  a  pump. 

Sewing  machine  motor.  Small  motors  may  now  be  at- 
tached to  the  table  of  a  sewing  machine  which  will  run  the 
machine  by  means  of  a  belt.  The  stopping  and  starting 
of  the  motor  and  the  control  of  the  speed  may  be  regulated 


ELECTRICITY  IN  THE  HOME 


153 


by  the  foot,  so  that  both  hands  are  left  free  to  guide  the 
work.  More  work  can  be  done,  because  more  stitches  per 
minute  may  be  taken  when  the  motor  is  used  than  can  be 
taken  when  the  machine  is  driven  by  the  foot. 

A  motor  may  be  used  to  operate  a  pump.  If  one  has  the 
pneumatic-tank  system  of  supplying  water  to  the  house, 
the  motor  may  be  attached  to  the  pump  and  arranged  to 
start  and  stop  automatically  according  to  the  pressure  in 
the  tank. 

Electric  bell.  One  very  common  application  found  in 
many  homes  is  the  electric  bell.  This  illustrates  the  ap- 


Daor 


Drawing  Room    Dining  Room 
FIG.  53.  —  Bell  circuits. 

plication  of  two  electric  appliances,  the  bell  itself  and  the 
cell  that  operates  it.  By  pushing  a  button,  the  circuit  is 
closed  and  the  current  from  the  battery  operates  the  bell. 
When  the  finger  is  taken  off  the  button,  the  circuit  is 
broken  and  the  bell  stops  ringing. 

The  most  important  part  of  a  bell  is  a  special  kind  of 
magnet  called  an  electromagnet.  Magnets  may  be  formed 
in  several  ways.  There  are  found  in  nature  natural  magnets 
called  lodestones,  which  attract  iron.  Magnets  may  also 
be  made  by  rubbing  a  piece  of  steel  with  another  magnet, 
or  by  bringing  iron  or  steel  under  the  influence  of  a  current 
of  electricity.  If  a  number  of  coils  of  wire  are  wound  around 


SCIENCE  OF  HOME  AND   COMMUNITY 


a  bar  of  soft  iron,  and  a  current  of  electricity  is  sent  through 
the  wire,  the  bar  becomes  a  magnet  and  will  pick  up  iron. 
This  is  called  an  electromagnet.  The  strength  of  the  magnet 
may  be  increased  by  increasing  the  number  of  turns  of  the 
wire  or  by  increasing  the  strength  of  the  current. 

This  form  of  magnet  is  very  useful  because  it  can  be  con- 
trolled. If  an  ordinary  bar  magnet  is  brought  near  some 
iron  nails,  they  are  taken  up  by  the 
magnet  and  remain  there  unless  shaken 
off.  If  an  electromagnet  is  brought 
near  iron  nails,  they  are  taken  up  by 
the  magnet  and  stay  there  only  as  long 
as  the  current  passes  through  the  wire. 
If  the  current  is  broken,  the  nails  drop 
off  at  once.  So  the  power  of  the  elec- 
tromagnet may  be  controlled  simply 
by  opening  and  closing  the  circuit. 

We  may  now  refer  to  figure  54  to 
see  how  the  electromagnet  works  in 
the  electric  bell.  It  is  bent  into  the 
form  of  a  horseshoe,  SN.  When  the 
button  P  is  pushed  down  and  a  current 
of  electricity  passes  through  the  wire, 
the  magnet  becomes  magnetized  and 
draws  down  the  iron  bar,  A,  called 
the  armature,  to  which  is  fastened  a 


FIG.  54.  —  Electric  bell. 


clapper  H.  When  this  is  drawn  down,  it  strikes  the  bell. 
At  the  same  time  that  the  armature  is  drawn  down,  the 
electrical  connection  at  the  point  B  is  broken,  and  so  no 
current  passes  through  the  electromagnet.  It  ceases  to  be 
a  magnet  and  so  no  longer  holds  down  the  iron  bar,  which  is 
then  brought  back  by  the  spring  S  to  which  it  is  attached. 
As  soon  as  this  happens,  the  contact  is  made  again,  and 
thus  the  operation  is  repeated. 


ELECTRICITY  IN  THE  HOME  155 

LABORATORY  EXERCISE  18 

Purpose.     To  study  the  working  of  an  electric  bell. 

An  electromagnet  is  an  important  part  of  the  electric  bell, 
so  in  order  to  understand  how  this  works  we  will  first  study 
magnets. 

A.    The  Magnet 

Apparatus.  Two  bar  magnets,  horseshoe  magnet,  pieces  of 
metal,  such  as  iron,  steel,  tin,  zinc,  a  dime,  a  copper,  a  nickel, 
piece  of  glass,  iron  filings,  darning  needle,  blue-print  paper. 

Directions,  a.  Magnetic  substances.  I.  Take  a  magnet  and 
try  a  great  many  substances  to  see  which  it  will  attract.  Find 
the  greatest  distance  that  a  piece  of  iron  is  attracted.  Put 
the  end  of  the  magnet  in  a  box  of  tacks.  By  trying  various 
portions  of  the  magnet  see  which  is  the  strongest  part.  Put 
the  magnet  in  iron  filings. 

2.  Test  needles,  pins,  pens,  etc.,  to  see  if  they  are  made  of 
iron  or  steel. 

b.  The  magnetic  field.     I.    Place  a  bar   magnet  on  the  table 
and  put  over  it  a  sheet  of  paper.     Sprinkle  iron  filings  over  this 
paper.     Make  a  drawing  showing  the  way  the  filings  arrange 
themselves.     Put  two  like  poles  of  two  bar  magnets  about  an 
inch  apart.     Over  these  put  a  piece  of  paper  and  on  it  sprinkle 
the  iron  filings.     Draw.     Do  the  same  with  two  unlike  poles. 
Draw.      What   is    the    difference   in   the  arrangement    of   the 
filings  ?     Place  a  horseshoe  magnet  under  the  paper  and  sprinkle 
the  filings. 

2.  To  make  blue  prints  of  the  magnetic  field.  Repeat  the 
previous  experiments,  only  instead  of  the  ordinary  paper,  use 
a  piece  of  blue-print  paper  over  the  magnets.  Place  in  a  shaded 
part  of  the  room  and  sprinkle  filings  on  the  paper.  Carefully 
place  a  piece  of  glass  on  the  filings  and  put  magnet  and  all  in 
the  sunlight  and  allow  to  stand  till  the  paper  becomes  bronze. 
This  will  take  from  five  to  twenty  minutes,  according  to  the 
light.  Then  shake  off  the  filings  and  wash  the  paper  in  several 
changes  of  water  and  then  dry. 

c.  How  to  make  magnets.     Rub  one  end  of  a  needle  on  one 
end  of  a  magnet,  rubbing  several  times  in  the  same  direction. 


156  SCIENCE  OF  HOME  AND   COMMUNITY 

Then  rub  the  other  end  of  the  needle  on  the  other  end  of  the 
magnet.  See  if  the  needle  will  pick  up  tacks.  The  blade  of  a 
jackknife  may  be  magnetized  by  rubbing  over  a  magnet.  Try 
bringing  another  needle  near  a  pole  of  a  magnet,  but  not  quite 
touching  it.  See  if  the  needle  becomes  magnetized. 

B.    The  Electromagnet 

Apparatus.  Large  nail  or  bolt  about  six  inches  long,  about 
twenty  feet  of  insulated  wire,  two  dry  cells,  tacks,  magnet. 

Directions,  i.  An  electromagnet  is  an  important  part  of  an 
electric  bell.  It  can  be  made  as  follows.  Wind  about  ten 
feet  of  insulated  wire  around  a  large  nail  or  bolt  as  threa4  is 
wound  on  a  spool.  Place  the  end  of  the  nail  in  a  pile  of  tacks. 
Is  it  a  magnet?  Connect  the  wire  with  a  dry  cell.  Is  it  a 
magnet  now?  Withdraw  the  nail  and  see  whether  the  coil 
will  pick  up  fewer  or  more  tacks.  Disconnect  the  cell.  What 
happens  ?  Connect  the  cell  again.  See  if  a  needle  can  be  mag- 
netized by  rubbing  against  the  nail. 

2.  Wind  five  feet  of  wire  around  the  nail  and  see  how  the 
number  of  tacks  it  lifts  up  compares  with  the  number  when 
ten  feet  of  wire  were  used.  Try  twenty  feet  and  note  the  dif- 
ference. Try  two  cells  and  compare  with  the  number  of  tacks 
lifted  when  one  cell  was  used  with  the  same  length  of  wire.  In 
what  ways  do  these  experiments  show  that  the  strength  of  an 
electromagnet  may  be  increased  ? 

C.    The  Electric  Bell 

Apparatus.     Electric  bell,  push  button,  cell. 

Directions.  Connect  the  bell  and  push  button  with  the  cell. 
Push  on  the  button  and  notice  what  parts  of  the  bell  move. 
Make  a  drawing  showing  the  connections  of  the  bell,  button, 
and  cell.  Make  a  careful  drawing  of  the  bell.  By  means  of 
arrows  show  through  what  parts  of  the  bell  the  current  passes. 

Cells.  A  very  simple  cell  may  be  made  by  putting  strips 
of  copper  and  zinc,  with  a  wire  attached  to  each,  into  a  weak 
solution  of  sulfuric  acid.  If  the  wires  are  brought  together, 


ELECTRICITY  IN  THE  HOME 


T57 


a  current  is  formed,  as  may  be  shown  by  holding  the  wire 
over,  and  parallel  to,  the  needle  of  a  compass.  The  needle 
will  be  turned  from  its  north  and  south  position.  The  cause 
for  this  current  is  the  difference  between  the  action  of  the 
acid  on  the  two  metals,  the  zinc  being  acted  on  more  than 
the  copper.  If  the  cell  is  watched,  bubbles  of  gas  will  be 
seen  to  form  around  the  zinc  and,  passing  across,  gather  on 
the  copper.  These  are  bubbles  of  hydrogen,  which  are  poor 
conductors  of  electricity.  After  a  while  so  many  bubbles 
collect  on  the  copper  that  the  current  cannot  pass  through, 
and  so  the  cell  ceases  to  give  any  current. 

In  order  to  make  a  cell  that  will  be  of  practical  use,  it  is 
necessary  to  find  some  way  of  preventing  the  accumulation 
of  this  gas  on  the  metal.  This  is  generally  done  by  putting 
in  the  cell  a  second  chemical,  which  unites  with  the  hydrogen 
before  it  collects  on  the 
metal.  A  number  of  dif- 
ferent chemicals  may  be 
used.  In  one  cell  copper 
sulfate  is  used,  which  causes  cop- 
per to  be  deposited  on  the  copper 
strip.  In  other  cells  a  compound 
is  used  which  gives  off  oxygen,  and 
this  unites  with  the  hydrogen. 

Classes  of  cells.  Two  types  of  cells 
are  commonly  distinguished,  the 
wet  and  the  dry.  The  Leclanche* 
cell  is  a  type  of  wet  cell  sometimes 
used  for  door  bells.  (See  figure  55.) 
Carbon  and  zinc  are  used  and 
placed  in  a  solution  of  sal  ammoniac.  The  carbon  is  placed 
in  a  porous  cup  and  surrounded  with  a  compound  which 
oxidizes  the  hydrogen. 

Dry  cells.     The  dry  cell  (see  figure  56)  is  now  largely  re- 
placing the  wet  cell  on  account  of  its  greater  convenience  for 


FIG.  55.  —  Leclanche"  cell. 


158 


SCIENCE  OF  HOME  AND   COMMUNITY 


handling.  It  is  not  really  a  dry  cell  but  a  moist  cell,  as  the 
chemicals  are  brought  into  contact  in  the  form  of  a  moist 
paste.  Most  of  these  dry  cells  are  modifications  of  the 

Leclanche  cell.  The  elements  used 
are  carbon  and  zinc,  and  the  chief 
chemical  is  sal  ammoniac.  The 
outer  shell  of  the  cell  is  made  of 
zinc.  Inside  this  is  a  mixture  of 
sal  ammoniac  and  plaster  of  Paris 
to  make  a  stiff  paste.  In  the  center 
is  a  rod  of  carbon  surrounded  with 
manganese  dioxid.  The  two  chem- 
icals are  separated  by  blotting 
paper.  After  the  cell  is  moistened, 
it  is  sealed  with  pitch  to  prevent 
the  water  from  evaporating.  If 
the  cell  really  did  become  dry,  it 
would  be  worthless. 


FIG.  56.  —  Dry  cell. 


LABORATORY  EXERCISE  19 

Purpose.  To  learn  how  the  cell 
used  to  operate  the  electric  door  bell  is  made. 

Apparatus.  Strip  of  sheet  zinc,  strip  of  sheet  copper,  each 
with  a  wire  attached.  Sulfuric  acid,  compass,  tumbler,  sal 
ammoniac  cell,  dry  cell  sawed  lengthwise  into  two  equal 
parts. 

Directions.  I.  A  simple  cell  may  be  made  as  follows.  Fill 
a  tumbler  about  two  thirds  full  of  water,  add  to  this  about 
one  twelfth  as  much  sulfuric  acid.  Put  the  strip  of  copper  and 
zinc  in  this  solution  in  such  a  way  that  they  do  not  touch. 
Notice  what  takes  place  on  the  surface  of  each  metal.  Connect 
the  two  wires  and  see  if  there  is  any  difference  in  what  happens 
on  the  surface  of  the  two  metals.  Hold  the  wire  north  and 
south  and  place  a  compass  directly  over  it.  What  happens  to 
the  needle  ? 

2.    The  sal  ammoniac  cell  is  very  commonly  used  to  operate 


ELECTRICITY  IN  THE  HOME  159 

door  bells.     Set  up  the  cell,  noting  the  different  parts.     Make  a 
drawing  of  a  longitudinal  section  through  the  cell. 

3.  Sometimes  dry  cells  are  used  to  operate  the  electric  bells. 
Make  a  drawing  of  a  dry  cell  cut  in  two  lengthwise.  Label  the 
parts  and  explain  the  use  of  each  part. 


HOME  PROJECT  16 

Purpose.  To  study  the  parts  of  an  electric  door  bell  outfit, 
and  to  fix  it  if  it  gets  out  of  order. 

Directions.  I .  If  you  have  an  electric  door  bell  in  your  home, 
study  it  to  see  how  the  different  parts  are  connected.  Make  a 
drawing  showing  the  bell,  push  button,  wires,  and  cell.  Notice 
the  kind  and  number  of  cells.  If  more  than  one  is  used,  show 
in  your  drawing  how  they  are  connected. 

2.  If  your  door  bell  is  out  of  order,  see  if  you  can  fix  it.  First 
test  the  bell  by  connecting  it  directly  with  the  battery.  Then 
look  at  the  cells.  They  may  need  either  a  new  zinc,  more  sal 
ammoniac,  or  simply  more  water  to  take  the  place  of  that  which 
has  evaporated.  Look  at  the  binding  posts  and  see  if  the  con- 
tacts are  tight.  Scrape  all  contacts  to  free  them  of  non-con- 
ducting materials  that  may  have  accumulated.  If  the  trouble 
is  not  with  the  cell,  look  at  the  push  button  to  see  if  the  contact 
here  is  all  right.  Examine  the  bell  to  see  if  the  connections 
with  the  binding  posts  are  secure,  and  if  the  vibrator  makes 
proper  contact.  Very  rarely  it  might  happen  that  the  wire 
was  broken  somewhere. 


SUPPLEMENTARY  QUESTIONS  FOR   CLASS  DISCUSSION 

1.  What  is  the  principle  involved  in  the  various  instruments 
used  for  cooking  by  electricity  ? 

2.  What    are .  the   advantages   of    using   electricity   in   the 
home? 

3.  What  uses  can  be  made  of  the  motor  in  the  home  ? 

4.  Explain  how  the  electric  bell  works. 

5.  How  do  cells  generate  electricity? 


160  SCIENCE  OF  HOME  AND   COMMUNITY 

REFERENCES 

Harpers'  Electricity  Book  for  Boys,  Harper  Bros.,   New  York 

City.     Chap.  2  (Cells). 
Kaister,  Electricity  for  the  Farm  and  Home,  Sturgis  and  Walton, 

New  York  City. 
Lancaster,    Electric    Cooking,    Heating,   and   Cleaning,   D.   Van 

Nostrand  Co.,  New  York  City. 


SECTION  D 
USE  OF  THE  HOME  GROUNDS 

CHAPTER  XI 
ORNAMENTATION  OF   HOME   GROUNDS 

What   steps   should  be  taken  in   order  to 
beautify  the  home  grounds  ? 

A  large  amount  of  pleasurable  and  profitable  work  in 
growing  plants  is  possible  in  the  home  grounds  by  a  little 
careful  planning.  The  possibilities  in  this  line  are  not 
generally  appreciated  and  improved.  Even  in  the  small 
city  lot,  with  only  its  back  yard  available,  a  great  deal  can 
be  done :  while  as  the  size  of  the  yard  increases,  the  possi- 
bilities increase  accordingly.  The  flower  garden  may  serve 
to  beautify  the  grounds ;  the  vegetable  and  fruit  gardens 
will  furnish  a  source  of  foods  of  the  best  kind  at  low  cost ; 
both  give  opportunity  for  healthful  outdoor  exercise  and 
furnish  a  source  of  pleasure  to  the  one  who  cares  for  them 
and  watches  their  development  through  the  seasons.  If  one 
has  a  large  yard,  the  vegetable  and  fruit  gardens  may  yield 
some  financial  return,  as  well  as  keep  the  home  table  supplied 
with  vegetables. 

The  plan.     Before  beginning  the  actual  work  of  planting, 

it  is  much  more  satisfactory  to  make,  first,  on  paper,  a  general 

plan  of  the  grounds.     This  may  be  done  in  late  winter  before 

any  work  can  be  done  outdoors.     One  should  then  send  to 

M  161 


\ 
162  SCIENCE  OF  HOME  AND   COMMUNITY 


FIG.  57.  —  A  meaningless  back-yard  planting,  and  an  unnecessary  drive. 

the  seed  houses  and  nurserymen  for  catalogs.  This  general 
plan  should  consist  of  a  map  of  the  grounds  drawn  to  a  proper 
scale,  showing  the  location  of  the  buildings,  walks,  and 
boundaries  (fences,  hedges,  etc.)  and  any  trees,  shrubbery, 
vines,  or  other  things  already  planted.  Then  on  this  plan 
should  be  arranged  such  other  plants,  in  the  desired  loca- 
tions, as  one  may  wish  to  set  out.  It  is  well  also  to  make 
separate  plans  of  the  flower  and  vegetable  gardens  on  a 
larger  scale,  showing  exactly  what  is  to  be  planted  and 
where.  These  plans  will  enable  one  to  work  to  better  ad- 
vantage in  the  spring  and  to  secure  more  satisfactory  results. 
A.  B.  C.  of  landscape  gardening.  In  planting  to  beautify 
the  grounds,  some  general  suggestions  may  be  given  with 
which  practically  all  gardeners  will  agree.  Three  essentials 
should  be  kept  in  mind,  which  some  one  has  called  the  A.  B.  C. 
of  landscape  gardening.  First,  the  shrubs  and  flowers 
should  be  placed  around  the  edge  and  borders  of  the  lawns, 
and  not  in  the  center,  which  should  be  kept  free  and  open. 
This  open  center  forms  an  important  part  of  the  general 
effect  and  also  tends  to  make  the  area  seem  larger  than  when 
the  shrubs  are  scattered  over  the  lawn.  Second,  the  plants 
should  be  grouped  in  masses.  If  one  wishes  to  plant  three 
shrubs,  instead  of  placing  them  so  far  apart  that  each  stands 


ORNAMENTATION  OF  HOME   GROUNDS 


163 


P^sttWfP^ 


FIG.  58.  —  Suggestions  for  improving  Figure  57. 

out  by  itself,  he  should  place  them  near  enough  to  each  other 
so  as  to  give  the  effect  of  one  mass.  Likewise  flowers  should 
be  planted  close  enough  to  give  a  mass  of  color.  Third,  do 
not  plant  in  straight  lines.  This  applies  especially  to  shrubs. 
If  a  border  is  to  be  made  of  these  plants,  they  should  be 
arranged  in  a  curving  line.  This  rule  does  not  apply  so 
closely  to  flower  gardens,  especially  in  small  gardens;  for 
very  good  effects  are  to  be  obtained  from  placing  flowers  in 
a  straight  border.  In  large  gardens,  however,  this  rule  may 
well  be  applied  by  having  the  border  follow  a  broad  curve. 

Shrubs.  Shrubs  furnish  one  of  the  best  means  of  orna- 
menting the  grounds.  Some  results  will  be  obtained  the 
first  year  of  planting,  but  it  requires  two  or  three  years' 
growth  to  produce  the  best  effects.  The  quickest  returns 
will  be  obtained  by  purchasing  from  a  nurseryman  the  shrubs 
partly  grown.  There  are,  however,  many  desirable  wild 
shrubs  which  may  be  taken  up  and  planted  in  the  home 
ground.  Some  shrubs  may  be  grown  from  cuttings,  but 
these  require  a  year  or  two  longer  to  mature  than  when 
they  are  obtained  partly  grown. 

The  shrubs  may  be  transplanted  either  in  the  fall  or  early 
spring,  the  fall  being  usually  the  better  time  except  in  the 
most  northern  states.  When  the  plant  is  put  in  the  ground, 


164 


SCIENCE  OF  HOME  AND   COMMUNITY 


the  hole  should  be  made  larger  than  the  expanse  of  roots 
so  as  to  furnish  soft  soil  in  which  the  new  roots  may  grow. 
If  the  soil  is  poor  it  should  be  enriched  with  manure  or 
fertilizer. 

Where  to  plant.  Shrubs  form  an  important  background 
for  the  yard  and  continue  to  grow  for  many  years,  improv- 
ing each  year  in  their  decorative  effects.  Not  only  may 
they  be  planted  along  the  borders,  walks,  and  driveways, 


FIG.  59.  —  Planting  of  shrubbery. 

but  in  front  of  porches  and  buildings,  especially  at  angles 
and  corners,  thus  helping  to  soften  the  hard  lines  of  the 
buildings.  Shrubs  may  often  be  used  as  a  screen  to  shut 
off  the  view  of  some  unsightly  object. 

What  to  plant.  In  deciding  what  shrubs  to  plant  one 
should  consider  hardiness,  size,  time  of  bloom,  and  color  of 
flower.  In  the  northern  tier  of  states  hardiness  is  the  first 
factor  to  consider,  as  many  shrubs  that  thrive  farther  south 
cannot  withstand  the  northern  climate.  In  these  northern 
sections  it  is  well  to  plant  liberally  of  native  shrubs. 


ORNAMENTATION  OF  HOME   GROUNDS  165 

The  size  of  shrubs  must  be  adapted  to  the  size  of  the  yard, 
only  the  smaller  shrubs  being  planted  in  small  yards.  In 
larger  yards,  several  tiers  of  shrubs  may  be  planted,  the 
tallest  in  the  background  and  the  smaller  ones  in  the  front. 
By  proper  selection  of  shrubs,  one  may  have  some  in  bloom 
all  the  season.  Even  in  winter  their  decorative  effects  may 
be  enjoyed  if  shrubs  are  planted  which  carry  their  fruit 
through  the  winter.  These  will  also  serve  as  a  means  of 
attracting  birds. 

The  following  table  is  given  for  reference  to  show  the  chief 
characteristics  of  a  few  of  the  more  common  shrubs. 


Small  Shriibs 


NAME 

HEIGHT 

TIME  or 
FLOWERING 

COLOR  OF  FLOWER 

Flowering  almond  . 
Japanese  barberry  .     . 
Deutzia  gracilis  . 

4  feet 
3-4  feet 
3-4  feet 

May 
June 
June 

Rose 

Red  and  yellow 
Rose  white 

Medium-sized  Shrubs 


Golden  bell    .... 

8  feet 

April 

Yellow 

Panicled  dogwood  . 

8  feet 

April-May 

White 

Hydrangea  paniculata 

6  feet 

Aug.-Sept. 

White 

Spirea  Van  Houttei 

6  feet 

June 

White 

Japanese  snowball  . 

7-9  feet 

May 

White 

Weigelia  Candida     .     . 

6-7  feet 

All  summer 

Pink 

Large  Shrubs 


Lilac     

10—  i  s  feet 

May 

White  and  purple 

Mock  orange 

10  feet 

June 

White 

Ninebark  

10  feet 

June 

White 

i66 


SCIENCE  OF  HOME  AND   COMMUNITY 


Native  Shrubs  Suitable  for  Transplanting 


NAME 

HEIGHT 

TIME  OF 

FLOWERING 

COLOR  OF  FLOWER 

Barberry  

6  feet 

March-April 

Yellow 

Clethra      

4-6  feet 

August 

White 

Red  osier  dogwood 

3-6  feet 

June-July 

White 

Smooth  sumac   . 

10  feet 

June-Aug. 

Yellowish  green 

Maple-leafed  viburnum 

6  feet 

May-June 

White 

Witch  hazel  .     .     .     . 

12  feet 

November 

Yellow 

Perennial  vines.  Vines  form  an  essential  feature  for  the 
decoration  of  the  home  grounds,  as  they  help  to  cover  the 
bare  side  of  a  building  with  a  wall  of  verdure.  They  are 
specially  valuable  for  buildings  of  stone,  brick,  or  concrete. 
The  Virginia  creeper  and  Boston  ivy  are  both  self-sustaining, 
as  they  develop  little  suckers  which  cling  to  the  support  on 
which  they  are  growing.  Vines  occupy  so  little  space  that 
they  may  be  grown  in  even  the  smallest  yard.  They  may 
be  trained  on  the  main  walls  of  the  house  or  around  the 
piazza.  It  is  well  to  have  them  trained  on  some  removable 
support  such  as  wires  or  wire  netting,  which  will  keep  the 
vines  away  from  the  woodwork  and  enable  them  to  be  taken 
down  when  the  house  is  painted.  Among  the  more  desirable 
vines  are  clematis,  Boston  ivy,  honeysuckle,  climbing  roses, 
trumpet  vines,  wisteria,  Virginia  creeper,  and  for  the  northern 
states,  Engelmann's  ivy. 

FIELD  EXERCISE  i 

Purpose.  To  study  those  shrubs  and  vines  that  are  adapted 
for  growing  in  the  home  grounds. 

Directions.  I.  Visit  parks,  private  grounds  (if  permission 
can  be  obtained),  and  thickets  where  wild  shrubs  grow  in  order 
to  identify  some  of  the  common  shrubs  and  vines  that  have 
ornamental  value.  The  flowering  effects  of  most  of  the  com- 
mon shrubs  can  best  be  observed  in  the  spring. 


ORNAMENTATION  OF  HOME  GROUNDS  167 

2.  Notice  to  what  extent  the  principles  explained  in  this 
chapter  are  carried  out  in  the  location  and  arrarjgement  of  the 
shrubs. 

3.  Make  a  study  of  the  different  kinds  of  shrubs  to  note  their 
attractive  features,  and  to  see  how  they  can  be  identified.     For 
each  shrub  studied,  record  the  following  points  in  your  note- 
book. 

A.  Name  of  shrub. 

B.  Leaves. 

a.  Arrangement  (opposite  or  alternate). 

b.  Kind  (simple  or  compound). 

c.  Margin  (entire,  toothed,  or  lobed). 

d.  Draw  leaf. 

C.  Flowers  (brief  description). 

D.  Fruit  (brief  description). 

E.  Height. 

F.  Features  that  make  it  adapted  for  planting  in  the 

home  grounds. 

G.  Chief  characters  by  which  identified. 

4.  A  similar  outline  may  be  used  for  vines.     Note  also  the 
method  of  climbing  and  the  support  on  which  the. vine  grows. 

5.  Draw  plans  of  some  attractive  yards  and  write  down  the 
names  of  the  shrubs  found  growing  there.     The  location  of  the 
shrubs  on  the  plan  may  be  indicated  by  small  circles  with  figures 
in  the  center  to  represent  different  kinds  of  shrubs. 

LABORATORY  EXERCISE  20 

Purpose.  To  make  a  plan  for  the  ornamentation  of  the 
home  yard.  (Late  winter  or  early 'Spring.) 

Directions,  i.  On  a  sheet  of  unruled  paper  make  a  plan  of 
your  home  yard,  on  as  large  a  scale  as  the  paper  will  allow. 
Try  ten  feet  to  an  inch.  On  this  represent  the  buildings  and 
sidewalks.  Also  indicate  by  means  of  small  circles  shrubs  and 
vines  already  planted. 

2.  Plan  first  for  the  shrubs.  Consider  the  kinds  to  select, 
their  location  and  arrangement,  following  the  suggestions  al- 
ready given  in  this  chapter.  Use  small  circles  to  represent 


1 68  SCIENCE  OF  HOME  AND   COMMUNITY 

shrubs  and  put  figures  in  the  center  to  show  the  different  kinds. 
On  one  corner  of  your  paper  explain  what  each  circle  represents. 

3.  Next,  select  vines  and  indicate  their  location  on  the  plan 
by  means  of  circles. 

4.  Indicate  the  location  of  the  flower  garden. 

The  flower  garden.  Location.  The  flower  garden  may 
oe  placed  as  a  border  around  the  edge  of  the  yard,  bordering 
the  walk,  next  to  the  fence,  in  the  front  of  the  porch  or 
house,  or  in  front  of  the  shrubbery,  but  it  should  not  be 
placed  in  the  center  of  the  lawn.  Most  plants  grow  better 
in  the  direct  sunlight,  so  that  if  the  garden  is  placed  near 
the  porch  it  should  be  in  a  sunny  location.  In  selecting  the 
seeds  to  be  planted  one  needs  to  know  three  things  about 
the  flowers :  their  color,  time  of  blooming,  and  height.  If 
the  border  can  be  made  wide  enough  so  that  two  rows  can 
be  planted,  the  taller  should  be  planted  behind,  and  the 
shorter  ones  in  the  front.  By  noting  the  month  when  flowers 
are  in  bloom,  one  may  make  a  selection  so  that  the  garden 
will  have  some  flowers  in  bloom  during  the  entire  season. 
Such  combinations  of  colors  may  be  made  as  each  individual 
prefers. 

Perennials.  Perennials  are  plants  which  live  several 
years.  The  tops  die  down  in  the  fall ;  but  the  underground 
parts  live  during  the  winter  and  send  up  new  stalks  each 
spring,  and  so  require  little  care.  Each  year  they  increase 
in  size,  making  large  clumps,  and  pieces  of  the  root  may  be 
cut  off  and  used  to  start  new  plants.  On  account  of  their 
permanency,  perennials  may  well  form  an  important  part 
of  the  flower  garden.  Seeds  may  be  planted  in  April  and 
will  bloom  the  second  summer.  They  may  also  be  sown  in 
August  and  September,  in  which  case  many  will  flower  during 
the  following  summer.  The  seeds  are  rather  slow  to  germi- 
nate and  require  good  care.  Plants  may  also  be  bought  and 
set  out  in  the  spring. 


ORNAMENTATION   OF   HOME   GROUNDS 
TABLE  OF  PERENNIALS 


169 


NAME 

COLORS 

TIME  OF 
BLOOM  * 

HEIGHT 

Anemone  Japonica 

White,  pink 

Aug.—  Sept. 

2     feet 

Asters      .... 

Blue 

Sept  .-Oct. 

2-6    feet 

Bocconia  cordata  . 

White 

July,  Aug. 

3-6    feet 

Candytuft    . 

White 

May—  June 

|-i     foot 

Cardinal  flower 

Red 

July,  Aug. 

4    feet 

Chrysanthemum    . 

All  but  blue 

Sept.—  frost 

3    feet 

Columbine    . 

Blue,  white,  yellow 

May-June 

if-3  feet 

Fox  glove     .     .     . 

White,  rose,  purple 

June-July 

2—3    feet 

Gallardia 

Yellow 

July-Oct. 

2    feet 

Golden  glow      .     . 

Yellow 

Aug.  -Sept. 

6    feet 

Hollyhock    . 

White,  yellow,  rose,  purple 

Aug. 

4-5    feet 

Larkspur      .     .     . 

Blue 

June-July 

4    feet 

Moss  pink    . 

Pink 

May—June 

\  foot 

Peony      .... 

White,  rose 

June 

3    feet 

Poppies    .... 

Yellow,  scarlet 

June-July 

2-3    feet 

Sweet  William  . 

Pink,  red,  white 

Jure—  July 

\-\\  feet 

Perennials  for  shady  places :  anemone  Japonica,  bluebell, 
bugleweed,  columbine,  polyanthus,  shooting  star,  lily  of  the 
valley,  fox  glove,  lilies,  German  iris. 

Bulbs.  It  is  very  easy  to  raise  flowers  from  bulbs.  The 
labor  of  planting  them  is  small,  and  after  they  are  once  set 
out,  they  require  little  subsequent  care.  Most  of  the  fall 
bulbs  may  be  allowed  to  remain  for  several  years  in  the  same 
situation,  where  they  will  bloom  each  year.  Some  will  do 
better,  however,  if  they  are  taken  up  and  transplanted  every 
few  years. 

Fall  bulbs.  Bulbs  may  be  divided  into  two  groups  in 
accordance  with  the  time  of  planting,  fall  bulbs  and  summer 
bulbs.  Fall  bulbs  are  planted  in  the  fall  and  blossom  during 
the  spring  and  summer.  This  group  includes  most  of  the 
common  bulbs,  such  as  the  crocus,  hyacinth,  tulip,  narcissus, 
and  lily.  Summer  bulbs  are  planted  in  the  late  spring  and 
1  For  latitude  of  New  York  City. 


170  SCIENCE  OF  HOME  AND   COMMUNITY 

early  summer  and  blossom  during  the  summer  and  fall. 
Gladiolus  and  tuberose  are  examples  of  this  class. 

When  to  plant.  The  fall  bulbs  may  be  set  out  from  the 
first  of  October  until  the  middle  of  November.  About  the 
middle  of  October  is  the  best  time  for  the  latitude  of  New 
York  City.  After  the  bulbs  are  set  out,  they  develop  a  root 
system  before  the  ground  freezes  and  thus  they  are  able  to 
start  into  growth  as  soon  as  the  warm  spring  days  begin. 
Bulbs  may  be  set  out  up  to  the  time  the  ground  freezes, 
but  to  get  the  best  results  this  should  be  done  earlier  so  as  to 
allow  the  roots  time  to  develop. 

Where  to  plant.  The  bed  for  the  bulbs  may  be  located  in 
a  great  variety  of  places,  but  they  should  not  be  set  where 
water  is  apt  to  stand,  as  the  bulbs  may  decay.  One  of  the 
best  locations  for  bulbs  is  a  border.  This  border  may  be 
along  walks  and  drives,  in  front  of  shrubbery  and  fences, 
or  along  the  house  or  porch.  Groups  may  be  set  between 
shrubs,  and  crocuses  may  be  scattered  irregularly  over  the 
lawn.  Most  bulbs  do  fairly  well  under  trees  and  in  other 
shaded  places.  In  many  cases  the  bulb  starts  growth  so 
early  in  the  spring  that  the  flowers  appear  before  the  trees 
are  in  leaf.  Beds  of  definite  geometric  shapes,  such  as  circles 
or  stars  are  better  adapted  to  parks  and  large  estates  than  to 
small  yards. 

What  to  plant.  In  deciding  what  bulbs  to  select  and  how 
to  arrange  them,  one  needs  to  consider  three  things :  the 
height  of  the  plant,  the  color  of  the  flower,  and  the  time  when 
the  plant  is  in  flower.  The  plants  which  blossom  at  the 
same  time  may  be  so  arranged  according  to  color  as  to  suit 
each  one's  taste.  With  reference  to  the  time  of  blooming, 
the  bulbs  should  be  selected  so  as  to  give  a  continuous 
succession  of  flowers  from  early  spring  until  summer.  This 
may  easily  be  done  as  there  are  some  bulbs  in  flower  during 
all  this  season,  beginning  with  the  snowdrop,  which  blossoms 
in  March,  often  before  the  last  snow  disappears,  followed 


ORNAMENTATION  OF  HOME  GROUNDS 


171 


by  the  other  March  flowers  such  as  the  crocus,  glory  of  the 
snow,  and  scilla.  The  hyacinth  appears  in  April,  the  tulips 
and  daffodils  in  April  and  May,  and  the  lilies  from  June  to 
August. 

As  a  matter  of  convenience  for  reference,  some  of  the 
characteristics  of  a  few  common  bulbs  are  given  in  the 
following  table.  They  are  arranged  approximately  in  the 
order  in  which  they  flower.  The  times  of  blooming  are  for 
the  latitude  of  New  York  City. 


TABLE  FOR  BULBS 


NAME 

DEPTH 
TO  PLANT 
(Inches) 

DISTANCE 
APART 
(Inches) 

MONTH  IN 
BLOOM 

LENGTH 

OF 

BLOOM 
(Weeks) 

COLOR 

HEIGHT 
(Inches) 

Snowdrop    .     .     . 

2 

2 

March 

3 

White 

3-4 

Glory  of  the  snow 

2 

2 

March 

o 

Blue 

6-9 

Scilla       .... 

3 

4 

March 

Blue 

4-6 

White 

Crocus    .... 

3 

3 

March 

2 

Blue 

6-8 

White 

Yellow 

Hyacinth     .     .     . 

5 

6 

April 

3 

Red 

8-18 

Blue 

White 

Yellow 

Tulip  

4 

5 

April 

3 

Yellow 

10-18 

May 

White 

Red 

Narcissus     . 

5 

4-5 

April 

4 

White 

1  2-1  8 

May 

Yellow 

Lily  of  the  valley 

3-4 

6 

April 

3 

White 

6 

Lilies  

4-10 

12-24 

June 

4-8 

White 

12-48 

July 

Yellow 

August 

Red 

• 

How  to  plant.  Before  setting  out  the  bulbs,  the  soil  should 
be  thoroughly  spaded  to  a  depth  of  a  foot  or  a  foot  and  a 
half.  Like  other  plants  these  will  do  better  in  a  rich  soil, 


172  SCIENCE  OF  HOME  AND   COMMUNITY 

but  very  satisfactory  results  may  be  obtained  in  ordinary 
garden  soil.  Soil  may  be  enriched  by  adding  fertilizers  or 
decayed  manure. 

The  depth  at  which  the  bulb  should  be  planted  depends 
upon  the  size  of  the  bulb,  the  larger  ones  being  set  deeper ; 
this  depth  varies  from  two  inches  for  small  bulbs  like  snow- 
drop, to  twelve  inches  for  some  lilies.  The  depths  for 
the  various  bulbs  are  given  in  the  table  on  page  171.  A 
general  rule  is  to  cover  bulbs  one  and  a  half  times  their 
own  diameter,  with  the  exception  of  lilies,  which  should  be 
covered  about  three  times  their  own  diameter.  For  the 
more  northern  latitudes  it  is  well  to  protect  the  bulbs  by 
means  of  a  mulch  of  leaves  or  straw.  This  should  be  placed 
on  the  bed  after  the  ground  is  frozen  and  then  removed  in 
the  early  spring. 

HOME  PROJECT  17 

Purpose.  To  plant  bulbs  in  the  home  yard  so  as  to  get 
flowers  during  the  spring. 

Directions.  Find  some  place  in  your  yard  suitable  for  plant- 
ing bulbs.  During  the  fall  spade  it  thoroughly  and  plant  some 
bulbs,  following  the  suggestions  given  in  this  chapter. 

Summer  bulbs.  The  more  common  kinds  of  summer 
bulbs  are  gladiolus,  cinnamon  vine,  dahlia,  and  tuberose. 
Gladiolus  may  be  planted  from  the  middle  of  April  until 
the  last  of  June.  The  corms,  as  these  underground  parts 
are  called,  should  be  planted  about  four  inches  deep  and  six 
inches  apart.  The  flowers  have  a  great  variety  of  colors. 
The  cinnamon  vine  is  valued  for  the  rapidity  of  its  growth, 
reaching  a  height  of  from  ten  to  thirty  feet  in  a  single  season. 
It  may  be  set  out  the  latter  part  of  April.  The  dahlia  is 
one  of  the  most  popular  flowers,  blooming  in  August  and 
September.  The  part  planted  is  really  a  root  instead  of 
a  bulb,  but  it  may  be  considered  here.  The  roots  may  be 
planted  from  the  middle  of  May  until  the  first  of  July. 


ORNAMENTATION  OF  HOME   GROUNDS 


173 


They  should  be  set  about  three  inches  deep.  Tuberose 
bulbs  may  be  set  out  the  last  of  May,  and  they  should  be 
covered  about  an  inch.  The  last  flowers  appear  during  the 
latter  part  of  September. 

All  these  summer  bulbs  are  tender  and  must  be  taken  up 
in  the  fall  and  stored  during  the  winter.  After  'being  dug 
up,  they  should  be  left  in  the  sun  and  air  for  a  few  days  to 
cure,  and  then  they  should  be  stored  in  a  cool  dry  place 
where  they  will  not  freeze. 

Annuals.  Annuals  live  but  one  season.  The  seeds  are 
planted  in  the  spring,  the  plant  develops  rapidly  and  dies 
on  the  approach  of  cold  weather.  Among  the  annuals  are 
a  number  of  vines  which  grow  to  a  great  height  during  the 
season  and  make  a  very  effective  screen  for  a  porch.  The 
morning  glory  is  one  of  the  best  and  it  sows  itself,  that  is, 
some  of  the  seeds  which  fall  from  the  vines  during  the  sum- 
mer germinate  the  following  spring,  so  that  although  the 
plant  dies  each  season,  other  plants  come  up  from  the  seeds 
formed.  Among  the  low-growing  vines,  climbing  nasturtium 
is  one  of  the  best. 


FIG.  60.  —  Border  of  four  c 'clocks. 


174 


SCIENCE  OF  HOME  AND   COMMUNITY 


Table  of  annuals.  Some  annuals  are  hardy,  such  as  the 
sweet  pea,  and  may  be  planted  as  soon  as  the  ground  thaws 
in  the  spring ;  while  others,  such  as  the  portulaca,  are  tender 
and  cannot  be  planted  till  danger  from  frost  is  past.  Some 
of  the  characteristics  of  a  few  common  annuals  and  details 
regarding  the  planting  of  the  seeds  are  given  in  the  following 
table.  The  dates  given  are  for  outdoor  planting.  The 
seeds  may  be  started  in  the  house  before  this  and  then  trans- 
planted. In  this  way  the  flowers  may  be  secured  several 
weeks  earlier.  These  dates  are  for  the  latitude  of  New  York 
City ;  for  other  localities  allow  six  days  difference  for  each 
hundred  miles  in  latitude ;  north,  the  dates  for  planting  and 
time  of  bloom  are  later ;  south,  they  are  earlier. 

TABLE  OF  TWENTY-FIVE  COMMON  ANNUALS  ARRANGED  IN  THE 
ORDER  IN  WHICH  SEEDS  MAY  BE  PLANTED 


NAME 

HEIGHT 
(Feet) 

COLOR 

TIME  OF 
BLOOM 

TIME  TO 
PLANT 

DAYS  RE- 
QUIRED TO 
COME  UP 

DISTANCE 
TO  THIN 
OUT 
(Inches) 

Sweet  pea  .     . 

4-6 

Purple 
Scarlet 

June-Oct. 

March 

7-2O 

4 

White 

Yellow 

Pink 

Poppy,     Cali- 
fornia    .     . 

i 

Scarlet 
Yellow 

July-Aug. 

April    i 

12 

6 

Nasturtium    . 

1-6 

Orange 
Red 

July-Oct. 

April  15 

10 

6 

Yellow 

Alyssum     .     . 
Candytuft 

* 

White 
Red 
White 

July—  frost 
June-Sept. 

April  15 
April  15 

7 
4~9 

6 
6 

Phlox     .     .     . 

i 

Scarlet 
Pink 

Sept.  -Oct. 

April  15 

10 

6 

White 

Mignonette     . 
Pansy    . 

i 

Greenish 
Purple 
White 

July-Oct. 
Sept-Oct. 

April  15 
April  15 

10 

10-30 

6 
6 

ORNAMENTATION  OF  HOME   GROUNDS 


175 


TABLE  OF  TWENTY-FIVE  COMMON  ANNUALS  —  Continued 


NAME 

HEIGHT 
(Feet) 

COLOR 

TIME  OF 
BLOOM 

TIME  TO 
PLANT 

DAYS  RE- 
QUIRED TO 
COME  UP 

DISTANCE 
TO  THIN 
OUT 
(Inches) 

Zinnia    . 

1  1-2 

Red 

July-Oct. 

April  15 

,5 

6 

Scarlet 

Yellow 

Verbena     .     . 

I 

Purple 

June-Sept. 

April  15 

14-30 

8 

Red 

White    . 

Ageratum  . 

i 

Blue 

Aug.  -Sept. 

May  i 

7 

6 

Cornflower 

1-2 

Blue 

July-Sept. 

May  I 

5 

6 

Forget-me-not 

\ 

Blue 

June-  Aug. 

May  i 

5 

6 

White 

Four  o'clock  . 

2-3 

Crimson 

July-Oct. 

May  i 

12-14 

24 

White 

Yellow 

Morning-glory 

15-20 

Blue 

Aug.—  Oct. 

May  i 

5-6 

6 

Red 

White 

Sunflower  . 

5-8 

Yellow 

Aug.-Oct. 

May  i 

5 

24 

Aster     .     .     . 

i 

Blue 

Sept.-Oct. 

May  10 

5-10 

6 

Red 

White 

Balsam  .     .     . 

1-2 

Pink 

July-Aug. 

May  10 

8-10 

8 

Red 

White 

Coreopsis  .     . 

1-2 

Yellow 

Aug.  -Nov. 

May  15 

10-15 

8 

Brown 

Cosmos      .     . 

4-6 

Pink 

Oct.  -Nov. 

May  15 

5-10 

12-24 

Red 

White 

Marigold    .     . 

1-2 

Yellow 

Aug.-Oct. 

May  15 

5 

8 

Petunia 

1-2 

Magenta 

Sept.—  Oct. 

May  15 

10-30 

10 

White 

Stock,  ten  weeks 

I 

Pink 

July—  Aug. 

May  15 

4-8 

8 

Salvia    .     .     . 

2-3 

Scarlet 

Sept.-Oct. 

June  i 

7-14 

18-30 

Portulaca  . 

\ 

Red 

July-Sept. 

June  i 

5-15 

4 

White 

Annuals  for  shady  places  :  Clarkia,  forget-me-ns>t,  godetia, 
madia,  musk-plant,  nemophila,  pansy,  torenia. 


176  SCIENCE  OF  HOME  AND   COMMUNITY 

Comparison  of  annuals  and  perennials.  Annuals  and 
perennials  each  have  their  advantages.  The  chief  advan- 
tage of  the  annual  is  that  one  gets  much  quicker  returns, 
as  the  flowers  are  obtained  the  same  season  that  the  seeds 
are  planted.  This  is  an  important  consideration  to  people 
who  do  not  own  their  homes  but  rent  them  for  a  year  at  a 
time.  It  is  possible  to  obtain  a  greater  variety  of  combina- 
tions from  year  to  year.  Since  the  garden  is  started  en- 
tirely anew  each  year,  any  new  combinations  or  varieties 
can  be  tried.  With  the  perennials,  it  is  much  more  difficult 
to  make  changes  after  the  plants  are  once  established.  The 
seeds  of  most  of  the  annuals  germinate  more  quickly  than 
those  of  the  perennials,  and  so  the  annuals  are  more  easily 
raised  from  seed. 

The  chief  value  of  the  perennial,  as  the  name  implies,  is 
that  the  plant  is  established  for  many  years,  and  after  it  is 
once  started  it  requires  less  care  than  the  annuals.  With 
the  perennials  it  is  possible  to  make  the  flowering  season 
nearly  twice  as  long,  since  some  of  the  perennials  begin  to 
bloom  in  the  early  spring  and  from  this  time  on  a  continuous 
succession  can  be  obtained  till  late  fall.  The  first  of  the 
annuals  do  not  begin  to  bloom  till  well  on  into  the  summer. 
There  is  a  greater  variety  of  ways  in  which  perennials  may 
be  started,  as  either  the  seeds  or  plants  may  be  used,  and  the 
seeds  may  be  planted  either  in  the  spring  or  late  summer. 

The  ideal  arrangement  is  to  have^a  combination  of  both 
annuals  and  perennials.  The  perennials  may  make  the  chief 
background  of  the  garden,  and  spaces  may  be  left  between 
for  the  annuals  which  may  be  changed  from  year  to  year  as 
one  wishes. 

LABORATORY  EXERCISE  21 

Purpose.  To  make  a  plan  of  a  flower  garden.  (Late  winter 
or  early  spring.) 

Directions,  i.  On  a  sheet  of  unruled  paper  make  a  plan 
of  a  flower  garden  to  scale.  Select  some  portion  of  your  yard. 


ORNAMENTATION  OF  HOME   GROUNDS  177 

2.  In  selecting  the  flowers  take  into  account :  a,  the  duration 
(whether  annual  or  perennial) ;  b,  the  height ;  c,  the  time  of 
bloom ;  d,  the  color. 

3.  Select  the  flowers  from  the  lists  given  in  the  chapter, 
following  the  suggestions  given.     In  considering  color,  put  to- 
gether those  colors  that  will  best  harmonize. 

4.  Write  on  the  plan  in  the  proper  location  the  names  of  the 
flowers  selected,   and  after  each  name  write:  a,   the  height; 
b,  the  time  of  bloom ;  c,  the  color ;  d,  time  of  planting. 

FIELD  EXERCISE  2 

Purpose.  To  identify  some  of  the  cultivated  flowers  and  to 
note"~their  attractive  features.  (Fall  and  spring.) 

Directions.  I.  Visit  parks  and  private  grounds  when  acces- 
sible, and  study  the  flowers  found  there.  For  each  plant  studied 
record  the  following  points  in  your  notebook. 

A.  Name. 

B.  Flowers. 

a.  Colors. 

b.  Size  and  shape. 

c.  Arrangement. 

d.  Odor  (strong  or  weak,  pleasant  or  offensive). 

C.  Leaves  (record  the  most  conspicuous  features). 

D.  Height  of  plant. 

E.  Kind  (annual,  biennial,  or  perennial). 

F.  Chief  characteristics  by  which  identified. 

2.  After  you  have  finished  your  study  of  a  number  of  flowers, 
select  the  ten  that  you  like  best. 

Care  of  garden.  As  a  general  thing  one  will  not  need  to 
water  the  garden  except  during  a  very  dry  spell ;  but  when 
it  is  watered,  the  ground  should  be  thoroughly  soaked  for  a 
depth  of  several  inches.  A  mere  sprinkling  of  the  surface 
is  useless  and  sometimes  injurious  to  the  plants  because  it 
tends  to  bring  the  roots  towards  the  surface.  It  is  especially 
important  that  the  germinating  seeds  should  have  a  supply 
of  water. 


178  SCIENCE  OF  HOME  AND   COMMUNITY 

When  the  seedlings  have  reached  a  height  of  two  or  three 
inches,  they  should  be  thinned  out  to  the  distances  given 
in  the  table,  and  if  it  is  desired,  the  plants  pulled  up  may  be 
transplanted.  This  should  be  done  on  a  cloudy  day  or  late 
in  the  afternoon.  If  the  flowers  are  kept  picked,  the  plant 
will  continue  to  bloom  longer  than  if  the  flowers  are  allowed 
to  remain.  A  few  may  be  allowed  to  go  to  seed  so  that  they 
can  be  saved  for  planting  the  next  year. 

Wild  flower  and  fern  garden.  A  very  interesting  section 
of  the  flower  border  may  be  made  by  reserving  a  portion  for 
wild  flowers  and  ferns.  These  may  best  be  transplanted 
from  the  wild  in  the  late  fall  or  in  the  early  spring,  although 
they  may  also  be  transplanted  in  mid-season  if  done  care- 
fully. Notice  the  conditions  under  which  the  plants  grow 
in  nature,  and  put  them  in  that  part  of  the  flower  bed  which 
most  closely  imitates  those  conditions.  In  a  few  years  an 
interesting  collection  of  wild  flowers  may  be  brought  together. 
Ferns  are  among  the  most  beautiful  foliage  plants,  and  most 
of  them  will  thrive  on  the  shady  sides  of  the  house,  where  it 
is  difficult  to  get  anything  else  to  grow.  In  collecting  these 
wild  flowers  be  careful  not  to  destroy  plants  needlessly, 

and  to  avoid  exterminating  rare  plants. 

• 

HOME  PROJECT  18 

Purpose.  To  beautify  the  home  grounds  by  growing  orna- 
mental plants. 

Directions,  i.  Talk  the  matter  over  with  your  parents,  and 
If  they  are  willing,  do  some  ornamental  gardening  in  your 
home  yard.  You  can  at  least  have  a  flower  garden.  Perhaps 
you  can  do  something  in  planting  shrubs  and  vines.  There 
may  be  an  opportunity  to  earn  money  by  selling  flowers. 

2.  As  far  as  feasible  try  to  follow  the  plan  you  have  made. 
Study  the  chapter  carefully  to  find  out  the  ways  of  doing  things. 

3.  Make  a  plan  of  your  flower  garden;  also  make  a  record 
of  plants  raised,  filling  in  the  following  table. 


ORNAMENTATION  OF  HOME   GROUNDS 


179 


NAME  OF 
FLOWER 

DATE 
SEED 
PLANTED 

DATE  UP 

DATE  OF 
FIRST 
FLOWER 

DATE  OF 
LAST 
FLOWER 

TIME  IN 
BLOOM 

COLORS 

HEIGHT 
OF  PLANT 

SCHOOL  PROJECT  5 

Purpose.     To  beautify  the  school  grounds. 

Directions.  If  the  school  grounds  have  not  been  planted 
with  shrubs,  vines,  and  flowers,  and  if  there  is  an  opportunity 
to  do  something  along  this  line,  the  class  may  work  together 
to  help  ornament  the  school  grounds.  Permission  should  first 
be  obtained  from  the  school  authorities.  A  plan  of  the  ground 
should  be  made.  Then  means  should  be  discussed  of  obtaining 
the  needed  plants.  Native  shrubs  and  vines  are  available  with- 
out expense.  A  border  of  bulbs  may  be  set  out  in  the  fall.  If 
flowers  are  planted,  those  should  be  chosen  that  are  in  bloom 
during  the  school  session.  The  various  things  to  be  done  may 
be  divided  among  committees.  The  work  of  digging  and  plant- 
ing may  be  done  by  the  boys. 

SUPPLEMENTARY  QUESTIONS  FOR  CLASS  DISCUSSION 

1.  Why  is  it  better  to  begin  gardening  by  making  a  plan? 

2.  What  should  be  taken  into  account,  (a)  in  selecting  the 
kinds  of  plants  for  ornamentation,  (b)  in  setting  them  out  ? 

3.  What  is  the  special  value  of  vines  ? 

4.  Which  would  you  rather  have,  a  flower  garden  of  annuals 
or  one  of  perennials  ?     Why  ? 

5.  Why  are  bulbs  specially  desirable  to  plant? 

6.  How  should  bulbs  be  planted  and  cared  for  ? 

7.  What  care  does  the  flower  garden  require? 

8.  What  are  the  chief  values  of  gardening? 

REFERENCES 

Baker,    Yard  and  Garden,  Bobbs  Merrill  Co.,  Indianapolis,  Ind. 
Bailey,  Manual  of  Gardening,  Macmillan  Co.,  New  York  City. 


CHAPTER  XII 
THE  VEGETABLE   GARDEN 

What  are  the  things  to  be  done  in  order  to 
have  a  successful  vegetable  garden  ? 

Reasons  for  gardening.  There  are  at  least  three  reasons 
for  having  a  garden  —  profit,  pleasure,  and  health.  From 
the  practical  side,  a  garden  may  make  a  great  saving  in  the 
cost  of  living  by  furnishing  food  that  must  otherwise  be 
bought.  A  good-sized  garden  can  furnish  vegetables  not  only 
for  the  summer  but  for  the  winter  as  well,  because  the  excess 
may  be  stored  or  canned.  A  vegetable  garden  also  furnishes 
a  means  of  earning  some  money  during  the  summer,  as  fresh 
vegetables  can  usually  be  sold  to  the  stores  or  to  people  who 
have  no  garden.  There  is  also  the  possibility  of  canning 
vegetables  for  sale. 

Profitable  gardening.  The  following  instances  taken  from 
various  publications  show  to  what  extent  it  is  possible  to 
make  even  a  small  garden  furnish  vegetables  for  a  family. 
One  man  in  Illinois  reports  that  the  produce  grown  on  a 
small,  city,  back-yard  garden  (28  by  25  feet)  was  nearly  all 
that  was  needed  from  May  15  to  November  for  a  family  of 
three,  and  part  of  the  time  for  six.  Another  from  New 
Jersey  reports  that  a  suburban  garden  (22  by  34  feet)  was 
made  to  supply  all  the  vegetables  necessary  for  a  family  of 
three.  Another  man  from  Minnesota  reports  that  for  four 
years  a  small  garden  of  ^  acre  —  that  is,  a  plot  about  the 
size  of  an  average  city  lot  (25  by  100  feet)  — kept  a  family 

1 80 


THE  VEGETABLE  GARDEN 


181 


of  six  adults  abundantly  supplied  with  vegetables  all  the  year, 
with  the  exception  of  potatoes,  celery,  and  cabbage. 

In  order  to  show  what  can  be  done  in  small  gardens,  the 
following  records  of  what  has  actually  been  accomplished 
have  been  taken  from  various  publications  and  put  in  tabu- 
lar form.  The  values  given  represent  the  total  value  of  the 
products  and  not  the  profits.  Allowance  must  be  made  for 
expenses  to  estimate  the  profits.  These  returns  are  not 
those  obtained  from  the  average  garden,  they  are  much 
better  than  the  results  generally  secured;  but  they  show 
the  possibilities  under  proper  care.  These  instances  are  not 
taken  from  skilled  gardeners,  but  some  of  the  best  returns 
are  taken  from  school  gardens  worked  by  children  from  12 
to  1 6  years  of  age. 

TABLE  SHOWING  VALUE  OF  PRODUCE  RAISED 
Small  Gardens 


SIZE  or  GARDEN 

NUMBER 
SQUARE  FEET 

TOTAL 

VALUE  OF  PRODUCE 
PER  SQUARE  FOOT 
(Cents) 

RATE 

PER 

ACRE 

8X30 

240 

$  5 

2 

$  850 

(Average  for  250  school 

gardens) 

10X20 

200 

5 

2* 

1050 

22X34 

748 

29* 

4 

1700 

25X25 

625 

32 

5 

2IOO 

Large  Gardens 


100X220 

22,000 

70 

i 

150 

100X225 

22,500 

IOO 

% 

200 

(Average  for  ?6  gardens) 

100X150 

15,000 

no 

1 

325 

100X50 

5,000 

43 

i 

425 

100X25 

2,500 

4i 

if 

700 

100X45 

4,500 

138 

3 

1500 

182 


SCIENCE  OF  HOME  AND   COMMUNITY 


One  of  the  secrets  of  success  in  these  cases  was  the  practice 
of  double  cropping,  which  is  explained  on  page  186. 

Gardening  and  health.  Gardening  has  a  beneficial  effect 
on  health  in  two  ways  :  first,  it  furnishes  a  means  for  outdoor 
exercise,  which  is  an  essential  to  the  best  health  ;  and  second, 
it  furnishes  an  abundance  of  the  best  kind  of  fresh  food.  It 


^ ftevfe ' ..,  .--4  ;$£  '  ~  ^":^- ^c^§fii^^'-  - - 


:  ,*-v  •;•;•>  ,.;•••>  ••;;---    «     ••.;/- VVH^'.^W/!'--*-^'  -X'.v>  >a»>p,a' '''<"<•  •  •-    «'  i::-~, ;:.-.;.:..,..._ 

I    •   w 

'•   *^v"'  -•"  :'      "•    ^-fr  '1^,-V  •••'''"•-•  vr^'.V.^v^J.' 

fe^S^scig::fi;;        ,|gs 

fegggf^fe-f^'fc::'-  ":'~*:<itej»;t 


$$!*$'          tBfzZSXS** 

^f'^^^^J^-^ 
^ 

FiG.  61.  —  A  home  garden. 

is  undoubtedly  more  healthful  to  eat  freely  of  vegetables 
and  fruits  in  place  of  meats,  especially  during  the  summer, 
and  fresh  vegetables  just  picked  from  the  garden  are  better 
than  vegetables  that  have  been  kept  for  a  while. 

Pleasure  in  gardening.  There  is  a  great  amount  of  pleasure 
in  gardening.  Many  people  find  this  one  of  their  most  de- 
lightful hobbies.  It  is  interesting  to  watch  the  wonderful 
changes  that  take  place  from  the  time  the  first  seedling  ap- 


THE   VEGETABLE   GARDEN  183 

pears  above  ground  till  the  fully  matured  product  is  ob- 
tained. This  interest  is  increased  by  the  work  one  does  in 
helping  the  plants  grow,  through  the  killing  of  weeds  and  the 
cultivation  of  the  soil.  Another  very  attractive  feature  is 
the  fact  that  gardening  takes  one  out  in  the  open  amid 
pleasant  surroundings  at  a  time  of  the  year  when  nature  is 
at  her  best. 

And  furthermore  a  well-kept  garden  is  in  itself  an  attrac- 
tive feature  to  be  compared  in  some  ways  with  the  flower 
garden.  The  foliage  effect  of  many  plants  is  attractive. 
This  is  especially  true  of  the  carrot  with  its  fern-like  leaves. 
Some  garden  plants  like  peas  and  pumpkins  have  attrac- 
tive flowers,  and  the  corn  plant  with  its  erect  tassels  and 
drooping  silks  is  an  attractive  feature  of  the  garden. 

The  plan.  During  the  late  winter  or  early  spring  before 
the  planting  is  begun,  a  map  of  the  garden  should  be  drawn 
on  paper.  The  vegetables  to  be  planted  should  be  decided 
upon  and  the  names  written  in  the  proper  places  on  the 
paper ;  and  the  number  of  rows  of  each  kind  of  vegetable  and 
the  distance  between  the  rows  should  be  indicated.  This 
will  first  require  that  the  dimensions  of  the  garden  be  meas- 
ured and  recorded  on  the  plan. 

Kind  of  vegetables.  In  deciding  upon  the  vegetables  to 
be  planted  several  considerations  will  need  to  be  taken  into 
account,  such  as  the  size  of  the  garden,  the  time  required 
for  the  vegetables  to  mature,  and  the  succession  of  crops. 
If  the  garden  is  small,  those  vegetables  should  be  avoided 
which  require  a  very  large  area  for  the  returns  yielded. 
Among  these  are  melons,  pumpkins,  winter  squashes,  and 
potatoes. 

Varieties.  It  is  important  to  consider  the  matter  of  the 
most  suitable  variety  of  each  vegetable  planted ;  that  is, 
the  different  kinds  of  peas,  corn,  etc.  Varieties  differ  in 
yield,  taste,  size,  time  required  for  maturing,  and  character 
of  growth,  such  as  climbing  peas  and  beans  and  the.  dwarf 


1 84  SCIENCE  OF  HOME  AND   COMMUNITY 


.c 

=1 
=1 

»? 

m? 

—  c 

sj 

-1 

"J 

«f 

s| 

s! 

SOW: 

||  Parsley  Apr.  15 

Spinach  Apr.  15  ....  followed  I 

>y  .  .  .  .  Late  Corn  July  1  ... 

Onion  sets  Apr.  15  

(Apr.  15)       (Apr.  15) 
Radishes  .  .   Cabbage  .  .  Radishe 

s  .  .  Cabbage  .  .  Radishes  and 
plant                         so  on 

plant 
Early  Lettuce  Apr  15,  ..  . 

Beets  Apr  15     followed  by 

Tomato  plants  June  1  .... 

Carrots  Apr.  15  

Turnips  Apr   15     followed  by 

.  .Late  Lettuce  July  15  
.  .  Late  Carrots  July  1  .... 

.  .  .  Late  Beets  July  15  
.  .Late  Turnipj  July  15.  .. 
lants  Tiinp  1 

Peas  Apr.  15  ..    .  followed  by 

Beans  May  1         followed  by 

...    .     Beans  May  15       followed  by 

Pepper  plants  June  1  [  1  Egg  p 

Cucumbers  June  1  

Early  Corn  May  10     followed 

by  .  .Late  Spinach  Aug.  1  .  . 

FIG.  62.  —  Plan  of  a  vegetable  garden. 

or  bush  varieties.  There  are  early  peas  and  late  peas,  early 
corn  and  late  corn.  There  may  be  a  great  difference  in  the 
yield  of  different  varieties.  The  author  tried  an  experiment 
with  peas  one  season  to  compare  the  yield  of  different  varie- 


THE  VEGETABLE  GARDEN 


ties.  Nine  varieties  were  planted  side  by  side  in  the  same 
length  of  row  and  all  given  the  same  care.  A  careful  record 
was  kept  of  the  peas  picked  from  each  row. 

The  following  table  shows  the  result  of  the  trial. 


VARIETY 

TOTAL  YIELD 
(Quarts) 

TIME  TO  MA- 
TURE 
(Days) 

TIME  IN  BEAR 

ING 

(Days) 

Nott's  Excelsior 

1  1 

62 

A 

Alaska     

16 

66 

6 

Laxtonian 

IQ 

6l 

6 

Little  Marvel    

2O 

61 

•i 

Sutton's  Excelsior      .... 

23 

63 

5 

Advancer                    . 

24. 

67 

4" 

Dwarf  Telephone  

29 

71 

12 

Dwarf  Champion  

35 

73 

10 

Prince  Edward      .     .     .     .     . 

4i 

7i 

5 

It  is  seen  that  the  best  yielded  nearly  four  times  as  many 
as  the  poorest.  It  must  not  be  supposed,  however,  that  this 
same  difference  would  always  hold  with  reference  to  these 
varieties,  because  it  would  vary  according  to  climate,  soil, 
and  season.  But  this  illustrates  the  fact  that  there  is  a  great 
difference  between  varieties  for  any  given  situation.  One 
interesting  feature  about  gardening  is  the  opportunity  to 
try  experiments  with  the  different  varieties  and  find  which 
are  best  adapted  to  one's  particular  garden. 

Among  the  best  varieties  of  corn  for  flavor  and  tenderness 
is  the  Golden  Bantam,  which  seems  to  be  a  general  favorite. 
As  the  name  implies  the  ears  are  small  and  the  kernels  yellow. 
It  is  a  medium  early  variety. 

It  is  interesting  to  try  one  or  more  new  kinds  of  vege- 
tables each  year.  Among  these  may  be  found  some  that  are 
just  as  valuable  as  the  common  kinds  more  generally  grown. 

Parts  of  plants  eaten.  In  accordance  with  the  part  of 
the  plant  used  for  food,  vegetables  may  be  divided  into  the 


1 86  SCIENCE  OF  HOME  AND   COMMUNITY 

following  groups :  i .  those  whose  root  we  eat,  such  as  beet, 
carrot,  parsnip,  radish,  and  turnip  ;  2.  those  whose  stems  we 
eat,  such  as  potato  and  onion ;  3.  those  whose  leaves  we  eat, 
such  as  cabbage,  celery,  lettuce,  parsley,  and  spinach ;  4. 
those  whose  seeds  we  eat,  such  as  peas,  beans,  and  corn; 
5.  those  whose  fruit  we  eat,  such  as  cucumbers,  melons, 
pumpkins,  squash,  and  tomato;  6.  those  whose  flowers  are 
eaten,  such  as  the  cauliflower. 

Double  cropping.  Succession  cropping.  In  order  to  raise 
the  most  on  a  certain  area,  the  ground  should  be  kept  in  use 
all  the  time.  Raising  two  crops  on  the  same  area  is  called 
double  cropping.  There  are  two  kinds  of  double  cropping, 
succession  cropping  and  companion  cropping.  In  succession 
cropping,  as  soon  as  one  kind  of  vegetable  has  matured 
and  been  harvested,  something  else  is  planted  in  the  same 
place.  For  example,  radishes  and  lettuce  may  be  followed 
by  late  corn ;  early  beets  by  cauliflower  or  eggplant ; 
peas  by  summer  lettuce ;  early  corn  by  cabbage  plants,  or 
spinach. 

Companion  cropping.  In  companion  cropping  the  two 
crops  occupy  the  ground  at  the  same  time,  one  being  planted 
between  the  rows  of  the  other.  Those  plants  must  be  selected 
which  mature  at  different  parts  of  the  season,  one  early  and 
the  other  late,  so  that  the  early  crop  may  be  gathered  and 
the  plants  pulled  from  the  soil  before  they  shade  the  second 
crop.  Thus  corn  or  tomato  plants  may  be  planted  between 
rows  of  early  peas,  and  when  the  peas  have  been  picked,  the 
vines  are  pulled  from  the  soil  to/  give  room  for  the  other 
crops.  Other  examples  of  companion  cropping  are  radishes 
between  the  rows  of  beets  or  carrots,  the  radishes  maturing 
before  the  beets  or  carrots  need  the  room ;  squashes,  pump- 
kins, or  climbing  beans  planted  in  the  hills  of  corn ;  early 
onions  with  cabbage.  Giving  attention  to  double  crop- 
ping is  one  of  the  secrets  of  success  in  raising  large  crops  of 
produce  on  small  areas. 


THE  VEGETABLE   GARDEN 


i87 


Steef-tooth 
Kake 


Spa  eft 


LABORATORY  EXERCISE  22 

Purpose.     To  make  a  plan  of  a  vegetable  garden. 
Dkections.     I.    On  a  piece  of  unruled  paper  make  a  plan  to 
scale  of  some  part  of  your  yard  that  could  be  used  for  a  garden. 

2.  Follow  the  suggestions  given  in  this  chapter  on  garden 
making.      Plan  for  a  sue-  ' 

cession  of    crops    and  for 
double  cropping. 

3.  Select  the  vegetables 
you  wish  to  grow  from  the 
table  on  page  198.     Draw 
lines  on  the  paper  to  repre- 
sent rows.      On  each  line 
write  the  name  of  the  vege- 
table to  be  grown,  and  after 
it     (i)    distance    between 
rows,  (2)  date  of  planting. 
Use  all  the  space  and  make 
the  sum  of  the  distances 
between    the    rows    equal 
the  width  of  the  garden. 

Outfit.  The  tools  abso- 
lutely required  are  few  in 
number,  the  three  most  es- 
sential being  the  hoe,  rake, 
and  spade,  or  spading  fork. 
In  addition,  however,  a 
flat  file  for  sharpening 
the  hoe,  a  trowel,  and  a 
garden  line  will  prove 
very  useful.  Two  strong, 
pointed  stakes  should  be 
provided  to  use  with  the 
line.  If  one  has  a  large 
garden,  it  will  pay  to 
secure  a  wheel  hoe.  It  FIG.  64.  —  Wheel  hoe. 


l88  SCIENCE  OF  HOME  AND   COMMUNITY 

saves  many  backaches  and  enables  one  to  do  the  work  of  car- 
ing for  the  garden  in  very  much  less  time  and  with  much 
more  pleasure.  The  two  most  important  attachments  are 
the  hoes  and  the  cultivator  teeth. 

Preparation  of  soil.  In  order  to  get  the  best  results,  the 
soil  should  be  enriched  with  manure  or  fertilizer.  It  should 
be  plowed  or  thoroughly  spaded  as  soon  in  the  spring  as  it 
can  be  worked.  Special  attention  should  be  given  to  the 
preparation  of  the  soil  where  seeds  are  to  be  planted.  It 
should  be  gone  over  with  a  rake,  the  lumps  taken  out,  and 
the  top  soil  left  in  fine  condition. 

Planting  the  seeds.  The  garden  line  should  be  used  to 
lay  out  the  rows  straight.  The  garden  should  be  planted 
in  long  rows  rather  than  in  short  beds,  as  this  makes  the  work 
of  cultivating  the  garden  much  easier,  especially  if  a  wheel 
hoe  is  to  be  used.  If  one  row  is  more  than  it  is  desired  to 
plant  with  one  kind  of  seed,  then  the  remainder  of  the  row 
may  be  planted  with  some  other  seed  which  requires  about 
the  same  space  between  the  rows.  In  planting  seeds,  three 
things  need  to  be  considered,  the  depth,  time,  and  distance. 

Depth.  The  depth  of  planting  depends  chiefly  on  the  size 
of  the  seed,  the  larger  seeds  being  planted  at  a  greater  depth. 
A  general  rule  is  to  plant  a  seed  at  a  depth  of  two  or  three 
times  its  smaller  diameter.  The  depth  of  planting  a  few 
common  seeds  is  given  in  the  table  on  page  198. 

Time.  The  time  of  planting  the  first  seeds  depends  upon 
the  hardiness  of  the  seedlings  to  frosts.  This  time  varies  with 
the  latitude  and  with  the  season,  according  to  whether  the 
spring  is  early  or  late.  The  average  time  for  a  few  seeds 
in  the  latitude  of  New  York  City  is  given  in  the  table. 
Vegetables  may  be  divided  into  two  groups ;  hardy  and 
tender.  The  hardy  vegetables,  like  radishes  and  peas,  can 
stand  the  light  frosts  of  spring  and  so  may  be  planted  as 
soon  as  the  soil  is  in  good  condition  to  work.  The  tender 
vegetables,  like  cucumbers  and  tomatoes,  are  killed  by  the 


THE  VEGETABLE  GARDEN  189 

frosts  and  so  cannot  be  planted  till  the  danger  from  frost 
is  past,  usually  about  three  or  four  weeks  after  the  hardy 
vegetables  are  planted.  In  setting  out  tender  plants  like 
tomatoes,  it  is  well  to  wait  until  about  a  week  after  the  time 
when  the  seeds  of  the  same  vegetable  could  be  planted. 

Distance.  The  distance  of  planting  seeds  depends  on  the 
size  of  the  mature  plant.  Space  enough  should  be  allowed 
so  that  the  plants  will  have  room  enough  to  grow  without 
crowding.  Some  seeds  like  peas  are  scattered  along  the 
rows  in  drills,  while  others  like  corn  and  potatoes  are  planted 
in  hills  at  certain  stated  distances. 

LABORATORY  EXERCISE  23 

Purpose.  To  test  the  seeds  you  are  going  to  plant  in  your 
garden. 

Apparatus.     Two  plates,  pieces  of  cloth,  and  blotting  paper. 

Directions,  i.  Secure  your  seeds  early  enough  so  that  you 
can  test  them  before  the  time  of  planting  outdoors  arrives. 
If  any  of  them  should  prove  poor,  you  will  still  have  time  to 
get  some  more  seeds. 

2.  For  large  seeds  like  peas  secure  a  piece  of  cloth  and  fold 
into  four  thicknesses  a  little  smaller  than  the  plate.     Moisten 
the  cloth,  put  it  in  a  plate,  and  put  the  seeds  between  the  folds. 
Cover  with  the  other  plate. 

3.  For  medium  seeds  like  radish,  use  four  folds  of  blotting 
paper  and  put  the  seeds  between  the  folds. 

4.  For  small  seeds  like  lettuce,  use  two  folds  of  blotting  paper 
and  place  the  seeds  on  top  of  the  paper. 

5.  Keep  a  record  of  the  number  of  seeds  put  in  the  tester. 
Keep  the  seeds  in  a  fairly  warm  place  and  see  that  the  cloth  and 
paper  are  kept  moist.     At  the  end  of  two  weeks,  count  the  num- 
ber of  seeds  that  have  germinated  and  compute  the  per  cent 
that  this  number  is  of  all  those  planted.     If  the  per  cent  is  very 
low,  below  50,  it  will  pay  to  secure  new  seeds. 

Thinning.  It  is  very  important  that  the  young  plants 
should  be  thinned  out  when  they  are  two  or  three  inches  high. 


190  SCIENCE   OF   HOME  AND   COMMUNITY 

The  distance  to  which  they  should  be  thinned  is  given  in  the 
table.  When  .the  plants  are  crowded  together,  there  is  not 
room  for  all  to  develop,  and  the  result  is  a  large  number  of 
poor,  small  specimens  instead  of  several  good,  large  specimens. 
If  desired,  the  plants  pulled  up  may  be  transplanted. 

Succession  of  crops.  If  the  garden  is  large  enough, 
arrangements  should  be  made  for  a  succession  of  crops ; 
that  is,  the  same  kinds  of  seeds  should  be  sown  at  intervals 
of  a  week  or  two,  so  that  when  the  plants  from  the  first  seeds 
have  stopped  bearing,  then  those  from  the  second  will  be 
maturing.  This  succession  may  be  arranged  with  those 
vegetables  which  mature  quickly,  such  as  radish,  lettuce, 
peas,  beets,  corn,  and  beans.  Another  way  to  secure  a  suc- 
cession is  to  buy  varieties  which  require  different  lengths  of 
time  to  mature  and  plant  them  all  at  the  same  time.  Some 
vegetables  require  the  whole  season  to  mature  so  that  gener- 
ally only  one  crop  is  raised  ;  such  are  parsnips,  salsify,  melons, 
and  pumpkins.  Seeds  of  beets  and  turnips,  that  are  to  be 
stored  for  the  winter,  should  be  planted  about  the  middle 
or  latter  part  of  the  summer. 

How  to  get  early  vegetables.  Early  vegetables  may  be 
obtained  through  the  use  of  hotbeds,  cold  frames,  and  seed 
boxes.  A  hotbed  is  a  shallow  box  covered  with  glass.  It  may 
be  placed  on  the  surface  of  the  ground,  but  it  is  better  to  have 
it  sunk  into  the  ground  for  a  part  of  its  width.  The  dirt  in- 
side is  taken  out  and  a  thick  layer  of  fresh  horse  manure  is 
placed  in  the  bottom.  This  is  then  covered  with  soil.  The 
decaying  manure  furnishes  heat,  which  keeps  the  hotbed  up 
to  a  high  temperature.  In  this  such  plants  as  cabbage, 
lettuce,  celery,  and  tomato  may  be  started  from  one  to  two 
months  earlier  than  they  could  be  planted  outdoors.  The 
bed  must  be  carefully  watched.  The  cover  must  be  shut 
down  at  night  to  prevent  the  young  plants  from  freezing, 
and  opened  during  the  day  to  allow  ventilation.  The  bed 
must  also  be  watered.  These  plants  are  later  transplanted 


THE  VEGETABLE   GARDEN  191 

to  a  cold  frame,  where  they  are  gradually  hardened,  and  then 
they  are  set  out  in  the  garden.  If  one  has  a  large  enough 
frame,  some  plants  like  lettuce  may  be  allowed  to  mature 
in  the  hotbed. 

A  cold  frame  is  made  in  the  same  way  as  a  hotbed,  only 
no  manure  is  put  in  to  furnish  artificial  heat.  Besides  being 
used  to  harden  the  plants  started  in  the  hotbed,  it  may  also 
be  used  to  start  seedlings,  on  the  same  principle  as  the  hot- 
bed ,  but  later.  Seeds 
can  be  planted  in  the 
cold  frame  three  or 
four  weeks  earlier 
than  they  could  be  in 
the  garden.  A  simple 
cold  frame  can  easily 
be  made.  A  box  of 
any  desired  size  may 

J  J  FIG.  65.  —  Cold  frame. 

be  partly  sunk  into 

the  ground  in  a  sunny  location,  tipping  toward  the  south, 

and  then  covered  with  panes  of  glass. 

A  seed  box  is  a  shallow  tray  in  which  seeds  may  be  started 
indoors.  These  boxes  may  be  placed  in  a  sunny  window,  and 
three  or  four  weeks'  time  may  be  gained  on  the  season  in  this 
way.  Plants  like  corn,  melons,  and  cucumbers  that  are  grown 
in  hills  may  be  planted  in  strawberry  boxes  indoors  early  in 
the  season.  When  danger  from  frost  is  past  the  bottom  of  the 
box  may  be  cut  off  and  the  whole  box  sunk  in  the  ground. 

Transplanting.  Transplanting  is  best  done  on  a  cloudy 
day  or  late  in  the  afternoon.  It  is  well  to  water  the 
plants  a  few  hours  beforehand,  so  that  when  they  are 
taken  out  some  dirt  will  adhere  to  the  roots.  If  the  ground 
is  very  dry,  the  plants  should  be  watered  after  they  are  set 
out.  Not  only  may  plants  be  transplanted  from  the  hotbed 
and  cold  frame,  but  when  plants  like  beets  and  lettuce  are 
thinned  out,  the  extra  plants  may  be  set  out. 


192  SCIENCE  OF  HOME  AND   COMMUNITY 

HOME  PROJECT  19 

Purpose.     To  raise  some  early  vegetables. 

Directions.  Early  vegetables  sell  at  good  prices.  They  are 
also  very  desirable  for  the  home  table.  If  you  care  to  raise  them 
for  either  of  these  reasons,  study  up  all  you  can  about  hotbeds 
and  cold  frames  in  some  book  like  Bailey's  Manual  of  Gardening. 
Follow  the  instructions  you  find  there,  and  make  and  plant  a 
hotbed  or  cold  frame.  Keep  an  account  of  the  value  of  the 
plants  raised.  An  expense  account  may  be  kept,  like  that  sug- 
gested on  page  201. 

SCHOOL  PROJECT  6 

Purpose.  To  raise  seedlings  of  some  vegetables  in  the 
schoolroom  so  they  may  be  taken  home  and  planted  in  your 
gardens. 

Directions.  Those  who  are  interested  can  work  together  to 
raise  seedlings  of  some  plants  like  lettuce,  cabbage,  and  tomato 
in  boxes  in  the  schoolroom.  For  this  purpose  shallow  flats  can  be 
made  and  the  seeds  planted  in  them.  Care  should  be  taken  to 
see  that  the  plants  do  not  freeze  between  Friday  and  Monday. 
When  it  is  time  to  set  the  plants  outdoors,  they  may  be  divided 
among  the  members  of  the  class  and  taken  home. 

Cultivation  of  soil.  After  the  plants  have  once  got  started, 
the  essential  point  in  caring  for  them  is  to  hoe  the  ground 
around  them  often.  This  serves  three  purposes,  it  keeps 
down  the  weeds,  it  mixes  air  with  the  soil  for  the  roots  to 
use,  and  it  helps  retain  the  moisture  in  the  soil.  During 
the  winter  and  early  spring  the  ground  becomes  soaked  with 
water,  and  then  as  the  warm  weather  comes  on  the  water  evap- 
orates and  the  soil  becomes  dry.  There  is  usually  enough 
water  in  the  soil  in  the  spring  to  last  the  plants  nearly  all 
summer  if  it  can  only  be  kept  from  evaporating  and  thus 
retained  in  the  soil  where  the  roots  can  use  it.  The  water 
at  first  sinks  down  deep  into  the  earth  and  then  gradually 
rises  to  the  surface,  where  it  evaporates.  Between  the  par- 
ticles of  soil  are  small  pores  through  which  the  water  rises  by 


THE  VEGETABLE  GARDEN 

capillarity  in  much  the  same  way  the  oil  rises  through  a 
lamp  wick. 

Now  if  something  can  be  done  to  break  up  these  pores 
at  the  surface,  the  water  will  be  kept  within  the  soil.  If  the 
soil  is  stirred  the  pores  are  too  large  and  discontinuous  to 
carry  the  water  to  the  top.  Thus  the  loose  soil  on  top 
(mulch,  it  is  called)  forms  a  blanket  which  keeps  the  water 
in  the  soil.  When  the  ground  becomes  hardened,  as  after 
a  rain,  the  soil  packs  again,  so  that  the  garden  should  be 
hoed  as  soon  after  a  rain  as  the  soil  becomes  dry,  and  in 
general  it  may  be  said  that  the  soil  should  be  stirred  about 
once  a  week.  It  is  literally  true  that  one  of  the  best  ways 
to  water  a  garden  is  to  hoe  it.  It  is  seldom  necessary  to 
pour  water  on  the  garden  except  in  the  very  driest  times. 

Enemies  of  the  garden.  Weeds.  In  nearly  every  garden 
there  are  two  enemies  that  one  must  meet,  weeds  and  insects. 
Most  soil  is  filled  with  seeds  of  weeds,  some  of  which  may 


Rough  pigweed  Purslane 

FIG.  66.  —  Two  common  weeds  of  the  garden. 
O 


194  SCIENCE  OF  HOME  AND   COMMUNITY 

live  in  the  soil  for  many  years  and  then  germinate.  Some 
have  been  known  to  live  as  long  as  fifty  years.  It  is  a  com- 
mon thing  for  seeds  to  live  ten  or  fifteen  years.  So  when 
the  conditions  for  seed  germination  arrive  in  the  spring 
these  seedlings  spring  up  in  the  garden.  If  these  are  allowed 
to  grow,  they  reduce  the  yield  of  the  garden,  because  they 
rob  the  garden  plants  of  water  and  plant  food  in  the  soil, 
and  they  deprive  the  plants  of  sunlight  above  ground. 
Weeds  also  make  the  garden  look  unsightly,  and  one  of  the 
important  things  to  do  in  caring  for  a  garden  is  to  keep  down 
the  weeds  by  hoeing. 

FIELD  EXERCISE  3 

Purpose.  To  identify  the  most  common  weeds  found  growing 
in  vegetable  gardens. 

Directions,  i.  During  the  fall  a  trip  may  be  taken  to  some 
gardens  in  the  vicinity  in  order  to  identify  some  of  the  more  com- 
mon weeds. 

2.  For  each  weed  studied  record  the  following  points  in  your 
notebook. 

A.  Name. 

B.  Height. 

C.  Character  of  growth  (erect  or  prostrate). 

D.  Leaves. 

a.  Size  and  shape. 

b.  Arrangement  (opposite  or  alternate). 

c.  Margin  (entire,  toothed,  orlobed). 

d.  Make  drawing  of  leaf. 

E.  Flower  (brief  description). 

F.  Fruit  and  seeds  (brief  description). 

G.  Chief  characters  by  which  identified. 

Insects.  Insects  are  another  common  enemy  of  the  garden. 
Some  plants  grow  without  much  interference  from  insects, 
while  other  plants  are  almost  always  attacked  by  them. 
Insects  can  be  divided  into  two  groups  according  to  their 


THE  VEGETABLE  GARDEN  195 

method  of  doing  harm,  the  biting  insects  and  the  sucking 
insects.  The  biting  insects,  like  the  potato  beetle,  devour 
the  solid  tissues  of  the  plant,  usually  of  the  leaf  ;  the  sucking 
insects,  like  the  squash  bug,  suck  out  the  sap  from  the  plant. 
The  following  table  is  taken  from  Farmers'  Bulletin  818. 
It  lists  the  insects  most  likely  to  appear  in  the  vegetable 
garden  and  furnishes  information  in  regard  to  the  plants 
attacked  and  the  treatment  recommended. 


INSECT 


PLANTS  ATTACKED 


TREATMENT 


Eating  type : 
Tomato  worm  . 

Cabbage  worm 
Cucumber  beetles 


Potato  beetle 

Sucking  type : 
Squash  bug  . 


Aphids  (plant  lice) 


Tomato     . 
Cabbage  group  . 
Cucumber 


Potato,      eggplant, 
and  tomato    . 

Squash,     pumpkin, 
melons,  etc.    . 

Cabbage  group  and 
other  plants   .     . 


Hand  pick  or  spray  with 
arsenate  of  lead. 

Hand  pick  or  apply  arsen- 
ate of  lead. 

Cover  with  frames.  Ap- 
ply tobacco  dust  or  spray 
with  Bordeaux  mixture 
or  arsenate  of  lead. 

Hand  pick  and  apply  arsen- 
ate of  lead. 

Hand  pick;  spray  with 
kerosene  emulsion  or 
nicotine  sulfate. 

Spray  with  kerosene  emul- 
sion, a  solution  of  hard 
soap,  or  nicotine  sul- 
fate. 


To  destroy  the  sucking  insects,  the  plants  are  sprayed 
with  some  poison  like  kerosene  emulsion,  which  kills  the 
insect  by  contact  or  by  smothering  it.  To  destroy  biting 
insects  the  plants  are  sprayed  with  some  poison  like  lead 
arsenate,  which  is  the  best  poison  for  this  purpose.  Paris 
green  is  also  frequently  used.  The  insects  eat  this  with 
the  leaf  and  are  poisoned.  For  small  quantities  three  tea- 
spoonfuls  of  lead  arsenate  or  one  of  Paris  green  are  used 


196  SCIENCE  OF  HOME  AND   COMMUNITY 

with  a  gallon  of  water.  In  small  gardens  the  insects  may  be 
hand  picked  by  knocking  off  the  insects  with  a  stick  into  a 
dish  containing  kerosene.  When  setting  out  plants,  like 
tomatoes  and  cabbages,  they  may  be  protected  from  'cut- 
worms by  putting  tin  cans  or  a  collar  of  heavy  paper  around 
them.  A  simple  way  of  combating  the  cucumber  beetle  found 
on  vine  crops  is  to  plant  an  abundance  of  seeds  (10-1 5)  in  each 
hill.  The  harm  is  done  chiefly  to  young  plants.  The  beetles 
will  not  usually  kill  all  of  this  number,  and  after  the  plants 
have  become  larger  and  the  danger  is  past,  they  may  be 
thinned  out  to  three  or  four  plants.  Young  plants  can  also 
be  protected  by  setting  over  them  a  frame  covered  with 
cheesecloth. 

LABORATORY  EXERCISE  24 

Purpose.     To  study  the  activities  of  some  garden  insects. 

Apparatus.     Insect  breeding  cages,  garden  insects. 

Directions.  I.  Simple  breeding  cages  may  be  made  out  of 
shoe  boxes  by  cutting  a  hole  in  the  cover  and  fastening  over  it 
a  piece  of  mosquito  netting.  Or  a  lantern  globe  may  be  placed 
in  a  flowerpot  filled  with  moist  sand.  Any  glass  receptacle 
such  as  a  canning  jar  may  be  used. 

2.  Secure  insects  from  the  garden,  bringing  in  also  a  piece 
of  the  plant  on  which  they  are  feeding.     Keep  them  in  a  breed- 
ing cage  and  bring  in  fresh  leaves  each  day  to  feed  them.    Secure 
also  some  beneficial  insects  like  the  lady  beetle  and  larva  of  the 
lace-winged  fly. 

3.  Study  the  various  insects,  noting  in  each  case  :  (a)  general 
appearance  by  which  it  may  be  identified ;  (6)  nature  of  harm 
or  good  done;  (c)  stages  in  which  harmful  or  beneficial;  (d) 
method  of  eating ;  (e)  chief  methods  of  locomotion. 

4.  If  desired  the  insects  may  be  mounted  as  explained  in 
Hodges,  Nature  Study  and  Life,  Chapter  IV. 

Storing  vegetables  for  winter.  If  the  garden  is  large 
enough,  the  family  may  be  supplied  with  vegetables  not 


THE   VEGETABLE   GARDEN  1 97 

only  during  the  summer,  but  in  the  winter  as  well.  Many 
vegetables  may  be  stored  in  a  cool,  dry,  well-ventilated 
cellar  where  the  temperature  does  not  fall  below  freezing. 
A  cellar  containing  a  furnace  will  be  too  warm  and  dry  and 
vegetables  stored  in  it  will  wilt.  If  the  cellar  is  warmed, 
a  corner  may  be  partitioned  off  for  storing  these  vegetables 
and  ventilation  procured  through  a  cellar  window. 

Some  vegetables  such  as  parsnips  and  oyster  plant  may 
be  frozen  without  injury,  indeed  they  may  be  left  outdoors 
all  winter  and  dug  up  when  needed.  Other  vegetables  such 
as  potatoes,  beets,  carrots,  and  turnips  require  a  temperature 
above  freezing,  from  35  to  45  degrees,  and  the  last  three  will 
keep  better  if  buried  in  moist  sand.  If  the  cellar  has  a  dirt 
floor,  a  very  simple  way  of  storing  root  crops  is  to  dig  a 
shallow,  broad  trench  and  place  in  it  beets,  carrots,  turnips, 
parsnips,  and  salsify,  and  then  cover  them  with  the  dirt 
that  has  been  excavated.  Potatoes  will  keep  better  if  placed 
in  the  dark. 

Vegetables,  like  pumpkin  and  squash,  will  keep  better  at 
a  slightly  higher  temperature  than  that  required  for  root 
crops,  about  50  degrees,  and  the  air  should  be  moderately  dry. 

To  store  celery  secure  boxes  about  a  foot  wide  and  as  deep 
as  the  celery  is  high.  Cover  the  bottom  with  two  or  three 
inches  of  wet  sand.  Dig  up  the  celery  plants,  roots  and  all. 
Stand  them  on  the  sand,  packing  them  close  together.  Cab- 
bages and  onions  may  also  be  stored  in  a  cool  cellar.  Even 
tomatoes  may  be  kept  here  for  a  few  months.  Just  before 
the  time  for  heavy  frosts  pick  the  largest  green  tomatoes  and 
place  them  on  straw  in  the  cellar. 

Cleaning  up  the  garden.  In  the  fall  when  the  products 
have  all  been  harvested,  the  weeds  and  old  plants  should 
be  pulled  up  and  buried,  so  that  the  garden  is  all  ready  for 
the  next  spring.  This  gives  the  garden  a  neater  appearance 
and  kills  some  insects  found  on  the  weeds  that  might  make 
trouble  in  the  garden  next  season. 


SCIENCE  OF  HOME  AND   COMMUNITY 


The  following  table  gives  in  condensed  form  some  of  the 
more  important  facts  regarding  the  raising  of  a  few  common 
vegetables.  The  dates  for  sowing  seeds  are  for  the  latitude 
of  New  York  City.  They  indicate  the  times  for  the  first 
and  last  sowing. 


NAME 

SEEDS  FOR 
100  FEET 
OF  Row 

DATE  TO 
Sow 

DEPTH  TO 
PLANT 
(Inches) 

Rows 

APART 

(Feet) 

PLANTS 
IN  Rows 
(Inches) 

DAYS  RE- 
QUIRED TO 
COME  UP 

TIME  TO 
MATURE 
(Days) 

Radish     .     .     . 

I  OZ. 

Apr.  15 

\ 

i 

1-2  1 

4 

20-40 

Sept.  i 

Lettuce   .     .     . 

\  oz. 

Apr.  15 

I 

i 

4-6  i 

4-8 

60-90 

Aug.  15 

Onion  (sets) 

i  qt. 

Apr.  15 

2 

ii 

3 

— 

90-120 

May 

Peas         .     .     . 

1-2  pt. 

Apr.  15 

3 

zi 

i 

7-10 

40-80 

June  i 

Beets  .... 

2  OZ. 

Apr.  15 

i 

i 

3-4  J 

6 

60-80 

Aug.  i 

Cabbage 

ioz. 

Apr.  15 

\ 

2 

18 

6 

90-130 

July  i 

Parsnip    . 

\  oz. 

Apr.  15 

\ 

ii 

3-4  > 

12-15 

125-160 

June  i 

Carrot     .     . 

I  OZ. 

Apr.  15 

i 

ii 

2-3  1 

8-9 

75-110 

June  i 

Turnip     .     .     . 

\  oz. 

Apr.  15 

i 

i* 

3-4  1 

4 

60-80 

Aug.  i 

Potato     .     .     . 

Sib. 

Apr.  15 

3-5 

2 

15-18 

20 

80-140 

June  i 

Corn   .... 

tpt." 

May  i 

2-3 

2* 

30-30 

8 

60-100 

July  10 

Beans  (bush)     . 

ipt. 

May  i 

2 

ti 

2-3 

8 

40-65 

Aug.  10 

Beans  (lima)     . 

rqt. 

May  15 

2 

2j 

3 

14 

90-120 

July  i 

Muskmelon  .     . 

£oz. 

May  15 

I 

7 

72 

8 

120-150 

June  i 

Cucumber    .     . 

*oz. 

May  15 

i 

S 

60 

4~i  i 

60-80 

July  i 

Squash 

*oz. 

May  15 

I 

4 

48 

ii 

60-80 

(summer) 

July  i 

Tomato 

— 

May  20 



3 

36 

— 

100-140 

(young  plants) 

June  15 

1  Distances  to  which  plants  should  be  thinned.     Seeds  should  be  planted  much 
closer. 


THE  VEGETABLE  GARDEN 


199 


TABLE  SHOWING  MONTHS  OF  PLANTING  SEEDS  AND  USING  PRODUCTS 

(For  latitude  of  New  York  City) 

(P  represents  the  months  seeds  may  be  planted :  E  represents  the 
months  the  products  may  be  eaten) 


VEGETABLE 

JAN. 

FEB. 

MAR. 

APR. 

MAY 

UNE 

TULY 

/VUG. 

SEPT. 

OCT. 

Nov. 

DEC. 

Radish    . 

P 

P 

P 

P 

P 

E 

E 

E 

E 

E 

E 

Lettuce  . 

P 

P 

P 

P 

P 

E 

E 

E 

E 

E 

Onions    . 

P 

P 

E 

E 

E 

E 

E 

E 

E 

Peas   .     . 

P 

P 

P 

P 

E 

E 

E 

E 

Beets  .     . 

P 

P 

P 

P 

P 

E 

E 

E 

E 

E 

E 

E 

E 

E 

E 

Cabbage 

P 

P 

P 

E 

E 

E 

E 

E 

E 

Parsnip   . 

P 

P 

E 

E 

E 

E 

E 

E 

E 

E 

Carrot     . 

P 

P 

P 

P 

E 

E 

E 

E 

E 

E 

E 

E 

E 

Turnip    . 

P 

P 

P 

E 

E 

E 

E 

E 

E 

E 

E 

Potato     . 

P 

P 

E 

E 

E 

E 

E 

E 

E 

E 

E 

E 

Corn  .     . 

P 

P 

P 

E 

E 

E 

E 

Beans 

P 

P 

P 

/ 

E 

E 

E 

Cucumber 

P 

P 

E 

E 

E 

E 

Summer 

squash 

P 

P 

E 

E 

E 

E 

Tomato  . 

P 

P 

E 

E 

E 

E 

Musk- 

P 

melon  . 

E 

E 

In  the  preceding  table  the  months  during  which  the 
various  seeds  may  be  planted  in  the  garden  are  shown  by 
the  letter  "  P  "  in  the  upper  half ;  the  months  during  which 
the  products  may  be  eaten  are  shown  in  the  lower  half  by 


200 


SCIENCE  OF  HOME  AND   COMMUNITY 


the  letter  "  E."  This  supposes  that  some  vegetables  are  stored 
in  the  cellar.  The  table  does  not  take  into  account  the  possi- 
bilities when  using  the  hotbed  and  cold  frame.  If  these  are 
used,  some  vegetables  can  be  planted  and  harvested  earlier. 

Vegetables  may  be  grouped  as  follows  according  to  the 
time  it  takes  them  to  mature. 


4-8  WEEKS 

8-12  WEEKS 

1  2-1  6  WEEKS 

14-20  WEEKS 

17-21  WEEKS 

Cress 

Beans 

Cabbage 

Eggplant 

Celery 

Radish 

Beets 

Onion  sets 

Pumpkin 

Melons 

Spinach 

Carrot 

Parsley 

Tomato 

Onions  (seeds) 

Corn 

Potato 

Parsnip 

Cucumber 

Salsify 

Lettuce 

Squash  (winter) 

Peas 

Squash  (summer) 

Turnip 

HOME  PROJECT  20 

Purpose.     To  raise  vegetables. 

Directions,  i.  If  you  have  room  in  your  home  yard  and 
your  parents  are  willing,  start  a  vegetable  garden.  It  may  be 
either  to  raise  vegetables  for  home  use  or  to  sell.  First  make 
a  plan  of  the  garden.  Show  it  to  the  instructor  to  see  if  he 
has  any  suggestions  to  offer  on  it. 

2.    Keep  a  record  something  like  the  following. 


NAME  OF 
VEGETABLE 

VARIETY 

DATE  or 
PLANTING 

LENGTH  OF  Row 

DATE  ABOVE 
GROUND 

DATE  FIRST  CROP 
PICKED 

DATE  LAST  CROP 
PICKED 

TOTAL  YEELD 

VALUE  AT 
MARKET  PRICES 

THE  VEGETABLE  GARDEN 


201 


3.  Figure  out  the  total  value  of  all  the  produce  raised,  and 
then  find  the  value  of  the  produce  per  square  foot  of  the  garden. 

4.  Keep  an  expense  account  in  accordance  with  the  follow- 
ing outline. 


AMOUNT 
PAID  OUT 

DATE 

AMOUNT 
RECEIVED 

DATE 

Totals     . 

Amount 
earned     . 

HOME  PROJECT  21 

Purpose.  To  test  different  varieties  of  some  one  kind  of  veg- 
etable. 

Directions.  Secure  the  seeds  of  as  many  kinds  or  varieties 
of  one  kind  of  vegetable  as  you  can,  and  see  which  are  best 
suited  to  your  garden  and  which  you  like  the  best.  Send  to 
seedsmen  for  catalogs.  For  instance,  if  radishes  were  chosen, 
a  record  like  the  following  could  be  filled  out. 

VARIETIES  OF  RADISHES 


NAME  OF 
VARIETY 

DATE  OF 

PLANTING 

DATE  OF 
FIRST  CROP 

DAYS  TO 

MATURE 

SIZE 

SHAPE 

COLOR 

FLAVOR 

YIELD 

HOME  PROJECT  22 

Purpose.     To  raise  tomatoes  for  canning. 

Directions.  Perhaps  some  of  you  would  like  to  raise  tomatoes 
for  canning.  If  so,  write  to  the  Division  of  Publications,  U.  S. 
Department  of  Agriculture,  Washington,  D.  C.,  and  ask  for  Far- 
mers' Bulletin  521,  "  Canning  Tomatoes  at  Home  and  in  Club 
Work."  It  is  sent  free.  This  bulletin  gives  a  number  of  recipes 
for  tomatoes  and  explains  how  girls  may  earn  money  by  selling 
canned  tomatoes.  It  gives  a  number  of  records  showing  how 
girls  have  made  from  #23.00  to  #78.00  in  a  season. 


202  SCIENCE  OF  HOME  AND   COMMUNITY 

SUPPLEMENTARY  QUESTIONS  FOR  CLASS  DISCUSSION 

1.  Of  what  value  is  the  vegetable  garden? 

2.  What  things  should  be  considered  in  deciding  on  the  kind 
of  seeds  to  plant  ? 

3.  How  may  the  most  be  raised  in  a  small  area? 

4.  What  are  the  advantages  of  cold  frames  and  hotbeds  ? 

5.  What  things  must  be  considered  in  planting  seeds? 

6.  What  care  does  the  vegetable    garden  require  after  the 
seeds  are  planted? 

7.  How  may  one  have  vegetables  in  the  winter? 

8.  Which  would  you  rather  have,  a  flower  garden  or  a  vegeta- 
ble garden?     Why? 

REFERENCES 

Bailey,  Manual  of  Gardening,  Macmillan  Co.,  New  York  City. 

Bennett,  The  Vegetable  Garden,  Doubleday,  Page  &  Co.,  New  York 
City. 

Rockwell,  The  Home  Vegetable  Garden,  J.  C.  Winston  Co., 
Philadelphia. 

Maynard,  The  Small  Country  Place,].  B.  Lippincott  Co.,  Phila- 
delphia. 


CHAPTER  XIII 

THE   FRUIT   GARDEN 

How  may  fruits  be  raised  in  a  small  garden  ? 

Fruits  have  not  been  grown  in  small  yards  as  generally  as 
have  vegetables  because  the  latter  mature  in  a  single  season, 
while  the  former  require  one  or  more  years  to  mature  after 
first  being  set  out.  On  the  other  hand,  fruits  have  the  ad- 
vantage that  they  bear  for  years  and  do  not  need  to  be 
started  anew  from  seeds  each  season.  They  form  such  a 
valuable  portion  of  our  diet  that  it  is  well  worth  while  to 
raise  them  at  home  so  that  they  may  be  obtained  fresher  and 
at  less  cost  than  when  purchased  in  the  market. 

Kinds  of  fruits.  The  fruits  grown  in  northeastern  United 
States  are  divided  by  the  fruit  grower  into  the  following 
classes  :  the  tree  fruits,  such  as  the  apple,  pear,  peach,  plum, 
and  cherry;  the  small  fruits,  such  as  strawberries;  the 
bush  fruits,  such  as  blackberry,  raspberry,  currant,  and 
gooseberry ;  the  vine  fruits,  such  as  the  grape. 

Plants  to  select.  In  deciding  on  the  kinds  to  plant,  one 
needs  to  take  into  account  the  following  considerations : 
the  size  of  the  yard,  the  size  of  the  mature  plant,  the  number 
of  years  before  the  plant  begins  to  bear,  and  the  month  in 
which  the  fruits  are  ripe.  Some  fruits  may  be  grown  in 
even  the  smallest  yards.  Grapevines  require  very  little 
space,  as  they  may  be  trained  on  fences,  porches,  or  build- 
ings, if  there  is  not  room  for  a  separate  grape  arbor.  Straw- 
berries also  require  little  space  and  are  well  adapted  to 

203 


204  SCIENCE  OF  HOME  AND   COMMUNITY 

small  areas.  The  bush  fruits  require  more  room,  and  yet 
at  least  one  row  can  be  set  along  the  fence  or  walk.  In 
medium-sized  yards  a  few  of  the  smaller  tree  fruits  may  be 
raised,  such  as  the  peach,  cherry,  and  plum ;  while  in  large 
yards  room  may  be  found  for  a  few  apple  and  pear  trees. 

In  Farmers'  Bulletin  154,  "  The  Home  Fruit  Garden," 
published  by  the  U.  S.  Department  of  Agriculture,  is  given 
the  following  list  of  fruit-bearing  plants  that  can  be  grown 
on  an  area  of  60  by  80  feet.  It  comprises  474  plants  dis- 
tributed among  9  kinds  of  fruit  as  follows :  32  grape  vines, 
1 8  dwarf  pear  trees,  6  peach  trees,  6  cherry  trees,  6  dwarf 
apple  trees,  6  plums,  20  plants  blackberries,  40  blackcaps, 
49  red  raspberries,  and  300  strawberry  plants. 

From  the  same  publication  is  taken  tne  following  list  of 
varieties  for  a  city  lot,  the  varieties  being  chosen  with  special 
reference  to  northern  Ohio.  This  list  requires  130  plants, 
divided  among  1 2  kinds  of  fruits : 

Apples,  4  trees — i  Red  Astrachan,  i  Golden  Sweet,  i 
Baldwin,  i  Fallanater. 

Peaches,  4  trees — i  Early  Canada,  i  Yellow  Rareripe, 
i  Early  Crawford,  i  Late  Crawford. 

Pears,  2  trees —  i  Bartlett,  i  Duchess  (dwarf). 

Plums,  2  trees  —  i  Wilder,  i  Lombard. 

Quinces  —  2  Champion. 

Apricots  —  i  Motezumet. 

Grapes,  10  vines  —  5  Concord,  5  Niagara. 

Raspberries,  20  bushes  —  10  Gregg,  10  Cutbert. 

Blackberries,  20  bushes  —  10  Taylor,  10  Agawam. 

Currant,  10  bushes  —  5  Victoria,  5  White  Grape. 

Gooseberries  —  5  Downing. 

Strawberries  —  50  Brandywine. 

Time  to  mature.  The  time  required  for  plants  to  come 
into  good  bearing  varies  from  one  to  ten  years.  Fruits 
may  be  divided  into  four  groups,  according  to  the  time 
before  they  bear  good  crops :  the  strawberry,  in  two  years ; 


THE  FRUIT  GARDEN 


205 


the  grape  and  bush  fruits  in  three  years ;  the  peach,  cherry, 
and  plum  in  five  years ;  and  the  apple  and  the  pear  in  ten 
years.  In  each  case  some  fruits  will  be  borne  earlier  than 
this. 

Succession  of  fruits.  Another  thing  to  consider  is  the 
season  of  the  year  when  fruits  are  ripe,  so  that  one  may 
select  the  proper  fruits  and  varieties  to  furnish  a  succession 
of  fresh  fruits  during  the  whole  season.  The  same  kinds  of 
fruit  may  mature  at  different  times  according  to  the  variety, 
so  that  by  selecting  both  an  early  and  a  late  variety,  the 
time  of  fruit  bearing  may  be  extended.  The  fruits  may 
be  divided  into  three  groups,  according  to  the  time  when 
they  ripen :  the  early  fruits,  including  the  strawberry  and 
cherry ;  the  midsummer  fruits,  such  as  the  currant,  goose- 
berry, raspberry,  blackberry,  and  peach  ;  and  the  late  fruits, 
such  as  the  grape,  pear,  and  apple. 

In  the  following  table  are  given  a  few  facts  in  brief  form 
for  reference. 


FRUIT 

DISTANCE  TO  SET 

TIME  TO  BEAR 
GOOD  CROPS 

MONTH  RIPE 

Strawberry      .     .     . 
Currant      .... 
Gooseberry 
Raspberry  .... 
Blackberry 
Grape 

3Xl|  ft. 

5X3  ft. 
5X3  ft. 
6X3  ft. 
6X4  ft. 
10  ft 

2  seasons 
3  seasons 
3  seasons 
3  seasons 
3  seasons 
"5  seasons 

June 
July 
July 

July 
July-Aug. 
Sept  —  frost 

Peach     

18  ft 

5  seasons 

August 

Cherry 

20  ft 

e  seasons 

June  —  Tulv 

Plum      .... 

IS  ft 

5  seasons 

August 

Apple  (standard) 
Apple  (dwarf)      .     . 
Pear  (standard)   .     . 
Pear  (dwarf)    . 

35ft. 

12  ft. 
20  ft. 
10  ft. 

10  seasons 
5  seasons 
12  seasons 
5  seasons 

Aug  -frost 
Aug.—  frost 
Aug  .-frost 
Aug  -frost 

The  distances  here  given  are  those  used  in  large  orchards, 
but  for  the  home  garden  these  distances  can  be  made  con- 


206  SCIENCE   OF  HOME   AND    COMMUNITY 

siderably  less,  thus  allowing  a  larger  number  of  plants  to  be 
grown.  To  compensate  for  this  crowding,  the  soil  will  need 
larger  amounts  of  fertilizers  and  thorough  cultivation. 

Fall  or  everbearing  strawberries.  One  of  the  most  inter- 
esting developments  in  the  fruit  world  during  recent  years 
has  been  the  appearance  of  the  fall,  or  everbearing,  straw- 
berry. This  has  the  great  advantage  that  it  bears  fruit 
the  same  year  it  is  planted.  It  is  set  out  in  the  early  spring 
at  the  time  the  first  seeds  are  planted  in  the  vegetable  garden, 
and  in  about  three  months  it  begins  to  bear  fruit,  at  about 
the  time  we  get  our  first  corn  and  tomatoes.  It  continues 
bearing  till  the  heavy  frosts  of  the  fall  kill  the  blossoms. 
Every  garden  can  have  its  fall  strawberries  as  easily  as  it 
has  peas  and  corn. 

The  plants  should  be  ordered  during  the  winter  from  some 
reliable  nurseryman.  They  cost  more  than  ordinary  straw- 
berries, but  after  the  first  expense  the  gardener  can  raise 
his  own  plants,  as  explained  later  in  the  chapter.  Among  the 
best  varieties  are  Progressive  and  Superb.  The  best  variety 
will  be  different  for  different  localities.  In  southern  Minne- 
sota the  author  tried  three  varieties  side  by  side  and  found 
that  the  Progressive  yielded  six  times  as  many  berries  as 
Americus,  and  twelve  times  as  many  as  Superb.  In  other 
localities  the  results  would  be  different,  but  one  can  soon 
learn  after  one  or  two  trials  the  variety  best  adapted  to  his 
conditions. 

The  plants  should  be  set  in  the  spring  as  soon  as  the  ground 
can  be  worked.  Two  systems  have  been  used  for  growing 
strawberries,  the  hill  system  and  the  mat  ted -row  system. 
In  the  hill  system  the  runners  are  all  kept  cut  off ;  in  the 
matted-row  system,  they  are  allowed  to  grow  and  form  a 
mat.  (See  figure  67.)  For  the  fall  strawberries  the  hill 
system  is  better.  In  a  small  garden  where  the  cultivation 
is  to  be  done  by  hand,  the  plants  may  be  set  from  18  to  24 
inches  apart  each  way.  For  horse  cultivation,  they  will  need 


THE   FRUIT   GARDEN 


207 


FIG.  67.  —  Matted  row  system  of  raising  strawberries. 

to  be  set  30  inches  apart.  In  setting  out  the  plants  care 
should  be  taken  not  to  set  the  plant  so  shallow  as  to  have 
some  of  the  roots  exposed,  nor  on  the  other  hand  should  it 
be  set  so  deep  as  to  cover  the  growing  part  of  the  plant. 
(See  figure  68.) 

The  soil  should  be  hoed  frequently  the  same  as  for  any 
plants,  and  the  blossoms  that  appear  in  the  spring  should 
be  picked  off.  If  these  blossoms  are  allowed  to  develop, 
the  berries  will  not  be  worth  picking ;  whereas  if  the  flowers 
are  picked,  more  nourishment  goes  to  the  roots  and  they  be- 
come stronger  and  better  fitted  for  the  work  to  be  done  later 
in  the  season.  The  runners  should  be  cut  off  with  a  sharp 
hoe  or  a  pair  of  scissors.  As  a  result  larger  and  better  berries 
are  obtained.  It  is  also  much  easier  to  keep  out  the  weeds. 

During  the  middle  of  the  summer,  blossoms  appear  again 
and  these  may  be  allowed  to  grow.  In  about  three  months 


208  SCIENCE  OF  HOME  AND   COMMUNITY 

from  the  time  of  planting,  the  first  berries  may  be  picked 
If  they  are  offered  for  sale,  they  are  usually  put  in  pint  boxes, 
and  will  bring  about  twice  as  much  as  the  spring  berries. 
If  one  plans  to  sell  the  berries  it  is  well  to  put  some  straw 
between  the  rows  to  keep  the  berries  clean.  But  this  straw 
has  the  disadvantage  that  it  interferes  with  cultivation  and 
so  enables  the  weeds  to  grow. 

These  plants  will  also  bear  the  following  spring  if  given 
proper  care.     In  the  late  fall  they  should  be  covered  with 


b  a, 

FIG.  68.  —  Setting  out  strawberry  plants,   b,  too  shallow ;  c,  too  deep ;  a,  just  right. 

straw  to  a  depth  of  two  or  three  inches.  This  protects  them 
from  the  alternate  thawing  and  freezing  of  the  winter  and 
early  spring  that  injures  the  roots.  In  the  spring,  about  the 
time  that  the  gardens  are  planted,  the  plants  are  uncovered. 
The  danger  of  uncovering  too  early  is  that  the  late  frosts 
may  kill  the  blossoms.  If  the  strawberry  patch  is  small,  the 
straw  may  be  taken  off  and  the  bed  cultivated  till  the  berries 
are  nearly  ripe,  then  the  straw  should  be  placed  back  to 
keep  the  berries  clean.  If  the  patch  is  too  large  to  remove 
all  the  straw,  that  over  the  plants  may  be  parted  and  placed 
between  the  rows. 


THE   FRUIT  GARDEN 


209 


These  same  plants  will  also  bear  again  the  following  fall, 
making  three  crops  in  two  years.  After  the  spring  crop  is 
harvested,  the  straw  should  be  entirely  removed  from  the 
bed  and  the  soil  cultivated.  The  runners  should  be  cut 
the  same  as  the  first  season. 

Propagation  bed.  After  one  has  decided  on  the  variety  he 
wishes  to  grow,  he  can  raise  his  own  plants  without  any 
expense.  A  small  corner 
may  be  used  for  a  propa- 
gation bed.  The  plants 
should  be  set  out  about 
three  feet  apart  and  the 
blossoms  picked  off  during 
the  entire  season.  All  the 
runners  should  be  allowed 
to  grow.  In  the  late  fall 
the  bed  should  be  covered 
with  straw.  In  the  early 
spring  the  straw  is  re- 
moved and  the  plants  dug 


FIG.  69.  —  Runner  of  strawberry  plant. 


up  and  set  out  as  already 

explained.     A  single  plant 

may  develop  from  20  to  50  runners.     One  great  advantage 

of  raising  one's  own  plants,  besides  the  saving  of  expense, 

is  the  fact  that  a  larger  per  cent  of  the  plants  will  live,  and 

they  get  a  better  start  than  when  shipped  from  a  distance. 


HOME  PROJECT  23 

Purpose.     To  raise  fall  strawberries. 

Directions.  If  you  have  room  for  a  garden  in  your  home  yard, 
try  a  small  bed  of  fall  strawberries.  Send  off  during  the  winter 
and  get  the  catalogs  of  several  reliable  nurserymen,  and  pick  out 
the  varieties  that  seem  best  adapted  to  your  locality.  It  is  well 
to  try  at  least  two  kinds.  When  the  plants  come,  heel  them 
in  at  once,  that  is,  open  the  bunches  and  set  the  plants  in  a  trench 
p 


210 


SCIENCE  OF  HOME  AND   COMMUNITY 


and  cover  the  roots  with  soil.  They  will  keep  this  way  for  a 
week  or  two  if  necessary.  When  setting  them  out,  put  a  few 
in  a  propagation  bed,  so  that  you  will  have  some  plants  to  set 
out  next  year.  Follow  the  directions  given  in  this  chapter  in 
caring  for  the  plants. 

Keep  a  record  of  the  results  in  the  following  table. 


NAME  OF 
VARIETY 

DATE  OF 
IST  PICKING 

DATE  OF 
LAST  PICKING 

TIME  IN 
BEARING 

YIELD 
(Pints) 

Spring  berries.  The  method  of  raising  spring  berries  is 
much  the  same  as  the  fall  berries.  Different  varieties  are 
used  to  start  with.  The  blossoms  are  picked,  the  runners  cut 
off  if  the  hill  system  is  used,  and  the  plants 
are  covered  in  the  fall.  In  the  spring  the 
plants  are  uncovered  in  the  manner  already 
explained  for  the  fall  berries.  After  the  fruit 
has  been  picked,  the  bed  may  be  renewed  by 
cutting  off  the  tops  of  the  plants  and  raking 
off  the  straw.  The  soil  between  the  rows  is 
cultivated  thoroughly  and  most  of  the  old 
plants  cut  out,  leaving  a  few  to  send  out  a 
new  set  of  runners.  Thus  another  crop  is 
obtained  the  next  season.  Some  people  pre- 
fer to  use  the  bed  only  one  season  and  then 
plow  it  up. 

Bush  fruits.  The  bush  fruits,  that  is, 
raspberry,  blackberry,  currant,  and  goose- 
berry, are  midsummer  fruits  which  bear  well 
the  third  season.  In  many  yards  room  may 
be  found  for  at  least  one  row  of  bush  fruits  next  to  the  fence. 
These  should  be  planted  about  three  feet  apart. 

The  grape.     The  grape  is  especially  well  adapted  for  grow- 
ing in  a  small  yard.     The  plant  itself  occupies  little  space  and 


FIG.  70.  —  Perfec- 
tion currant. 


THE  FRUIT  GARDEN  211 

may  be  trained  on  any  upright  support,  such  as  a  fence, 
arbor,  porch,  or  wall  of  a  building.  If  a  building  is  to  be 
used  for  support,  it  is  well  to  attach  a  strip  of  woven  wire  to 
the  wall  and  fasten  the  vines  to  this.  In  addition  to  fur- 
nishing a  supply  of  fruit,  it  has  an  ornamental  value  as  a 
vine  to1  cover  bare  places,  or  furnish  shade  for  a  porch. 
When  the  young  plant  is  being  trained,  it  should  be  cut  back 
the  first  two  years  so  as  to  form  one  main  stem  with  two 
branches.  These  branches  are  brought  down  into  a  hori- 
zontal position  extending  in  opposite  directions  and  attached 


FIG.  71.  —  Downing  gooseberry. 

to  wire  or  other  support.  From  these  are  allowed  to  develop 
vertical  branches  on  which  the  fruit  is  borne. 

Tree  fruits.  The  fruit  tree,  on  account  of  the  time  it 
requires  to  mature  and  because  it  grows  large,  is  not  so  well 
adapted  to  the  small  garden  as  those  already  mentioned; 
but  a  few  of  the  small  tree  fruits,  the  peach,  plum,  and 
cherry,  may  well  find  a  place  in  the  medium-sized-  yard, 
and  the  apple  and  pear  in  larger  gardens.  While  waiting 
for  these  fruits  to  mature,  one  can  utilize  the  space  between 
with  small  fruits  and  vegetables. 

Dwarf  trees.  Dwarf  trees  of  the  apple,  pear,  and  peach 
are  often  raised.  These  are  much  smaller  than  the  ordinary 
kinds;  they  require  fewer  years  to  come  into  bearing; 
and  they  are  easier  to  care  for.  For  these  reasons  they  are 


212 


SCIENCE  OF  HOME  AND   COMMUNITY 


especially  adapted  for  planting  in  small  yards.  Some  kinds 
of 'peaches,  apricots,  nectarines,  and  pears  may  be  trained 
like  vines  on  arbors  and  buildings.  These  are  much  more 
expensive  than  the  common  kinds,  but  they  can  be  grown 
where  there  would  be  no  room  for  the  ordinary  fruit  tree. 
Another  device  which  may  be  used  in  small  yards  is  to 

graft  a  number  of  varieties  on  one 
tree,  so  that  it  is  possible  to  make 
a  single  apple  tree  bear  different 
kinds  of  apples. 

Propagation  of  fruits.  In  start- 
ing the  fruit  garden,  one  will 
generally  get  more  satisfactory 
results  by  purchasing  a  few  plants 
from  the  nurseryman;  later,  as 
they  mature,  new  plants  may  be 
grown  from  them. 

Runners.  The  strawberry  is 
propagated  by  means  of  runners, 
which  grow  out  from  the  plant 
in  abundance  and  take  root  and 
form  a  new  plant.  The  connec- 
tion with  the  old  plant  may  be 
cut  and  the  new  one  transplanted. 
In  one  year  a  large  number  of 
plants  may  be  raised  from  a  small  beginning.  (See  figure  69.) 
Cuttings.  The  currant,  gooseberry,  and  grape  may  be 
propagated  by  means  of  cuttings.  In  the  autumn,  after 
the  leaves  have  fallen,  stems  of  the  last  season's  growth  are 
cut  into  pieces  six  inches  long,  containing  at  least  two  buds. 
These  may  be  set  out  at  once  in  mellow  soil  in  the  garden, 
so  that  the  top  bud  is  just  below  the  surface.  Or,  the  cuttings 
may  be  tied  together  in  bundles  with  the  lower  ends  together, 
and  placed  in  a  trench  in  the  garden  with  the  butt  ends 
up,  and  covered  to  a  depth  of  three  or  four  inches  with  soil. 


FIG.  72.  —  Dwarf  pear  tree. 


THE   FRUIT   GARDEN  213 

The  cuttings  may  also  be  stored  in  a  cool  cellar  in  sand  or 
sawdust.  In  the  spring  they  are  taken  up  and  planted 
three  or  four  inches  apart  with  the  top  bud  just  at  the  sur- 
face of  the  ground.  In  the  fall,  after  the  roots  have  formed, 
the  cuttings  may  be  transplanted  to  their  permanent  loca- 
tion. Cuttings  of  currants  may  be  made  in  the  spring  and 
planted  at  once. 

Layering.  The  grapevine  may  also  be  propagated  by 
layering.  In  the  spring  or  early  summer  a  branch  of  last 
season's  growth  is  bent  down  and  buried  in  the  soil.  Roots 
form  at  this  place;  and  the  next  spring  the  stem  may  be 
separated  from  the  main  vine  and  the  plant  dug  up  and 
transplanted. 

HOME  PROJECT  24 

Purpose.     To  raise  fruits  in  the  home  yard. 

Directions.  If  you  have  room  in  your  garden,  set  out  a  few 
fruit  plants.  Room  can  usually  be  found  for  a  grapevine,  and 
a  row  of  bush  fruits  can  often  be  planted  along  by  the  fence  or 
border  of  the  yard.  Dwarf  fruit  trees  require  only  a  small 
space  and  give  returns  quickly. 

SUPPLEMENTARY  QUESTIONS  FOR  CLASS  DISCUSSION 

1.  What  does  one  need  to  consider  in  deciding  on  the  kinds 
of  fruits  to  be  raised  in  a  small  garden  ? 

2.  What  are  the  advantages  of  dwarf  fruit  trees? 

3.  What  steps  are  necessary  to  raise  fall  strawberries? 

4.  How  may  the  grape  be  raised  in  the  small  yard  ? 

5.  How  may  fruits  be  propagated  in  the  home  garden? 

REFERENCES 

Bailey,  Manual  of  Gardening,  Macmillan  Co.,  New  York  City. 

Maynard,  The  Small  Country  Place,  J.  B.  Lippincott  Co.,  Phila- 
delphia. 

Rockwell,  The  Home  Vegetable  Garden,  Part  3,  J.  C.  Winston  Co. ^ 
Philadelphia. 

Rockwell,  Making  a  Garden  of  Small  Fruits,  Macbride  Nast 
and  Co.,  New  York  City. 


CHAPTER  XIV 
POULTRY   KEEPING  AND   BEEKEEPING 

What  are  the  differences  in  the  care  required 
for  keeping  poultry  and  keeping  bees  ? 

POULTRY  KEEPING 

Extent  of  industry.  The  real  extent  of  the  poultry  in- 
dustry in  this  country  is  not  appreciated  because  it  is  divided 
among  so  many  people,  each  doing  only  a  small  business; 
but  the  aggregate  is  large.  The  value  of  the  annual  poultry 
product  on  farms  alone  was  estimated  in  1890  to  be  about 
$300,000,000 ;  and  the  amount  for  the  entire  country  must 
have  been  considerably  more.  At  the  present  time  the 
value  of  the  annual  products  may  be  said  to  be  approxi- 
mately a  half  billion  dollars. 

Use  of  small  areas.  While  but  few  people  devote  their 
entire  time  to  poultry  keeping  as  a  business,  it  is  an  industry 
which  can  be  adapted  to  almost  any  requirements,  from 
the  small  yard  which  will  allow  the  keeping  of  only  a  few 
hens  to  the  large  poultry  farm.  It  may  be  made  a  source 
of  food  for  the  family  or  of  income  under  many  conditions 
where  only  a  small  amount  of  time  can  be  devoted  to  it. 
The  business  can  be  started  on  a  small  scale  with  little 
outlay  of  capital  and  gradually  be  increased  to  whatever 
extent  one  desires.  In  fact,  it  is  better  to  begin  on  a  small 
scale  till  one  acquires  experience.  Successful  poultry  rais- 
ing demands  experience  and  attention  to  details  rather  than 
strength  for  most  of  the  work,  so  with  a  little  assistance  for  the 
heavier  work  it  may  easily  be  managed  by  girls  and  women. 

A  good  market  at  profitable  prices  can  always  be  found 

214 


POULTRY  KEEPING  AND   BEEKEEPING  215 

for  fresh  eggs  in  cities  and  large  villages.  Under  an  in- 
tensive system  a  large  number  of  fowls  can  be  kept  in  a 
small  space.  The  smaller  the  flock,  the  greater  the  re- 
turns usually  are  per  capita. 

Breeds.     The  various  breeds  of  fowls  may  be  grouped 
under  three  classes:  the  meat  breeds,  the  egg  breeds,  and 


FIG.  73.  —  Single-comb  White  Leghorns.     An  egg  breed. 


FIG.  74.  —  Barred  Plymouth  Rocks.     A  general-purpose  breed. 


2l6 


SCIENCE  OF  HOME  AND   COMMUNITY 


the  general-purpose  breeds.  The  Brahmas  are  an  example 
of  the  first,  the  Leghorns  of  the  second,  and  the  Wyandottes 
and  Plymouth  Rocks  of  the  third.  Under  average  condi- 
tions the  best  breed  will  probably  be  one  of  the  general- 
purpose  fowls,  those  which  are  well  adapted  for  both  meat 
and  egg  production.  It  is  more  profitable  to  raise  pure- 
bred stock,  even  though  the  first  cost  be  a  little  more. 


FIG.  75.  —  Trap  nest.    Hen  entering. 


$p 

FIG.  76.  —  Trap  nest.    Hen  trapped. 

Selection  of  the  best  stock.  One  essential  to  profitable 
poultry  keeping  is  the  selection  of  the  best  chickens  for  egg 
production.  In  every  flock  there  are  usually  some  hens 
which  do  not  lay  enough  eggs  to  pay  for  the  cost  of  feeding 
them.  This  selection  may  be  brought  about  in  two  ways. 


POULTRY  KEEPING  AND   BEEKEEPING  217 

As  the  chickens  are  maturing,  the  most  active  and  vigorous 
and  the  largest  may  be  selected  as  those  which  will  probably 
be  the  most  productive.  Another  method  is  the  use  of  the 
trap  nest.  This  is  a  nest  so  constructed  that  as  a  hen  enters 
a  nest,  she  is  shut  in  and  kept  there  until  released.  By 
putting  numbered  leg  bands  on  each  pullet,  the  number  of 
eggs  which  each  lays  in  a  certain  time  may  be  determined, 
and  so  the  best  layers  may  be  selected.  These  nests,  how- 
ever, require  close  attention  and  must  be  visited  se'veral 
times  a  day  to  release  the  hens  and  keep  an  account  of  the 
eggs  laid;  but  they  are  the  only  means  of  determining  the 
exact  number  of  eggs  laid.  Even  if  they  are  used  for 


FIG.  77.  —  Front  view  of  henhouse. 

only  a  few  weeks  at  a  time  during  various  seasons  of  the 
year,  they  may  be  a  great  aid  in  the  selection  of  the  best 
layers. 

Hatching  the  eggs.  The  question  of  whether  the  eggs 
shall  be  hatched  by  hen  or  incubator  depends  largely  on 
the  number  of  chickens  to  be  raised.  Small  numbers  can 
be  raised  very  satisfactorily  by  using  hens ;  large  numbers 
require  an  incubator.  While  this  and  the  brooder  that  is 
required  after  the  eggs  are  hatched  are  rather  expensive, 
there  is  the  advantage  that  they  can  be  used  at  any  time 
and  large  numbers  of  chickens  can  be  raised. 

Poultry  house.  Many  types  of  poultry  houses  are  in 
use.  The  essential  points  are  that  they  shall  be  so  arranged 
as  to  keep  dry,  receive  sunshine,  and  be  well  ventilated. 


218 


SCIENCE  OF  HOME  AND   COMMUNITY 


Many  poultry  men  are  providing  ventilation  by  leaving  a 
part  of  one  side  entirely  open,  protected  in  cold  and  stormy 
weather  by  a  cloth  screen. 

Care  of  poultry.  The  essential  points  in  the  care  of  hens 
may  be  briefly  summarized  under  the  following  heads  :  clean 
water  at  least  once  a  day,  grit,  oyster  shell,  a  dust  box  to 
keep  the  fowls  free  from  vermin,  and  the  proper  amounts 
and  kinds  of  food.  The  matter  of  food  is  one  of  the  details 


Ventj/afor 


FIG.  78.  —  Cross  section  of  henhouse  shown  in  figure  77. 

on  which  experts  do  not  agree.  Indeed  there  is  no  one 
method  of  feeding  which  is  best,  for  there  are  many  com- 
binations of  foods,  all  of  which  are  good.  The  essentials 
in  which  these  all  agree  are  that  in  connection  with  the 
grains  there  should  be  fed  some  form  of  meat  food,  such  as 
beef  scraps  and  some  green  vegetable  food,  such  as  cabbage 
•or  beets.  The  mixture  of  foods,  known  as  mash,  is  given 
dry  by  some  and  mixed  with  water  by  others.  It  has  been 
the  custom  to  give  the  mash  wet,  but  in  recent  years  ex- 
periments made  with  dry  mash  kept  constantly  before  the 
fowl  in  hoppers  have  given  very  satisfactory  results,  both  as 
regards  egg  production  and  the  saving  of  labor  in  feeding. 


POULTRY   KEEPING  AND   BEEKEEPING 


219 


Another  essential  generally  recognized  is  that  *  some  of  the 
food  should  be  given  in  such  a  way  as  to  require  exercise 
on  the  part  of  the  fowl  to  ob- 
tain it.     This  is  brought  about 
by  throwing  grain  in  a  litter 
of    straw    or    other   material, 
which  the  fowls  are  obliged  to 
scratch  over  in  order  to  obtain 
the  food. 

HOME  PROJECT  25 

Purpose.     To  take  charge  of 
a  small  flock  of  chickens. 

Directions,  i.  If  some  one  at 
your  home  keeps  chickens,  per- 
haps arrangements  can  be  made 
for  you  to  take  entire  charge  of 
a  small  flock.  Or  perhaps  you 
can  start  anew.  Either  fall  or 
spring  is  a  good  time  to  begin, 
with  a  few  setting  hens  and  raise  chicks.  In  the  fall  a  small 
flock  of  pullets  may  be  secured.  It  pays  to  get  good  stock  even 
if  it  costs  a  little  more.  Look  up  some  good  book  on  poultry  and 
try  to  care  for  the  flock  in  the  very  best  way.  Try  a  trap  nest 
for  at  least  one  month  in  the  winter.  Make  special  effort  to 
get  eggs  in  the  winter,  for  that  is  the  time  when  they  are  worth 
the  most,  and  the  ability  to  get  winter  eggs  is  one  of  the  tests 
of  successful  poultry  keeping. 

2.  Two  types  of  records  may  be  kept :  one  a  careful  descrip- 
tion of  the  steps  taken  in  caring  for  the  poultry;  such  points 
as  breed,  number  to  start  with,  shelter  provided,  method  of 
feeding,  raising  young  chicks,  total  number  of  eggs  each  month, 
average  number  for  each  pullet.  A  second  record  should  be  kept 
giving  a  statement  of  receipts  and  expenses.  This  may  be  kept 
in  some  such  form  as  the  following. 


FIG.  79.  —  A  method  of  keeping  drink- 
ing fountain  clean. 

In  the  spring  one  may  start 


220  SCIENCE  OF  HOME  AND   COMMUNITY 

MONTHLY  FINANCIAL  ACCOUNT 


AMOUNT  PAID  Our 

DATE 

AMOUNT  RECEIVED 

DATE 

Total  for  month 
Gain  or  loss 

BEEKEEPING 

Keeping  bees  is  another  of  those  home  activities  which 
one  may  undertake  on  a  small  scale  for  the  triple  purpose  of 
furnishing  the  tables  with  a  fresh  supply  of  wholesome  food, 
of  securing  some  financial  return,  and  of  finding  a  source  of 
wholesome  recreation  in  studying  the  wonderful  life  of  those 
insects.  The  number  of  hives  kept  should  be  determined 
by  the  conditions,  but  it  is  wise  for  the  inexperienced  to 
make  a  small  beginning.  From  caring  for  one  hive  for  a 
season,  one  may  secure  the  experience  needed  to  care  for  a 
larger  number  the  following  season. 

Kinds  of  bees  in  colony.  Honey  bees  have  been  cared 
for  by  men  for  centuries  for  the  honey  and  wax  they  produce. 
Some  of  these  colonies  have  escaped  from  hives  and  are 
now  found  wild,  making  their  homes  in  hollow  trees.  These 
bees  illustrate  the  high  type  of  development  made  possible 
through  instinct.  Honey  bees  are  social  insects;  that  is, 
a  large  number  live  together  in  a  community,  each  bee 
having  a  work  to  perform  for  the  benefit  of  the  whole  colony. 
Three  kinds  of  individuals  are  found  in  a  hive :  one  queen, 
several  hundred  drones,  and  from  fifteen  to  thirty  thousand 
workers.  The  queen  lays  the  eggs,  some  of  which  are 
fertilized  by  the  drones ;  and  upon  the  workers  fall  all  the 
other  tasks  of  the  colony. 

Combs.  The  combs  are  made  of  wax,  which  the  bees 
form  into  six-sided  cells.  This  wax  is  secreted  by  some  of 
the  workers,  which  gorge  themselves  with  honey  and  then 


POULTRY  KEEPING  AND   BEEKEEPING  221 

hang  motionless  until  the  wax  appears  on  the  outer  surface 
of  their  bodies  and  is  taken  off  by  the  other  workers.  Cracks 
in  the  hive  are  filled  by  means  of  a  kind  of  cement,  called 
propolis,  which  is  secured  from  the  buds  of  trees. 

Care  of  the  young.  The  queen  lays  the  eggs,  one  in  each 
cell,  and  may  lay  two  kinds,  fertilized  and  unfertilized. 
The  first  kind  develops  into  drones,  and  the  other  into 
either  workers  or  queens,  according  to  the  kind  of  feed  given 
them.  The  larvae  that  hatch  from  these  eggs  are  fed  by 
the  workers  on  a  rich  food  called  bee-jelly,  and  then  with 
honey  and  bee  bread,  after  which  the  cells  are  filled  with 
food  and  capped  with  wax.  In  about  two  weeks  more,  the 
adult  bees  emerge  from  the  pupal  state  and  gnaw  their  way 
through  the  wax  cap.  In  three  weeks  from  the  time  the 
eggs  are  laid,  the  adult  bees  come  from  the  cells.  They  then 
take  up  their  duty  of  feeding  the  larvae,  which  is  the  work 
of  the  newly  hatched  bees.  This  is  the  method  by  which 
drones  and  workers  are  reared,  but  to  produce  queens  a 
different  plan  is  followed.  A  larger  cell  is  made  by  tearing 
down  the  partitions  between  several  cells  and  preserving 
only  one  fertilized  egg.  When  this  hatches,  the  larva  is 
fed  entirely  on  bee-jelly  during  all  of  this  stage,  and  as  a 
result  a  queen  is  developed  instead  of  a  worker. 

Swarming.  In  order  that  the  number  of  colonies  may  be 
increased,  there  occurs  occasionally  during  the  summer 
what  is  known  as  swarming,  when  a  part  of  a  colony  leaves 
the  old  hive  and  starts  a  new  colony.  Ordinarily  there  is 
but  one  queen  in  a  hive,  but  before  a  swarm  is  to  go  out 
another  queen  is  allowed  to  hatch ;  thereupon  the  old  queen 
goes  away  with  a  part  of  the  colony,  leaving  the  new  queen 
in  the  old  hive. 

Food.  The  food  of  the  colony  consists  of  nectar  and 
pollen.  The  work  of  gathering  this  is  performed  by  the 
older  workers.  The  nectar  is  sucked  up  into  a  honey  sack, 
where  it  is  made  into  honey  and  then  thrown  out  to  be 


222 


SCIENCE  OF  HOME  AND   COMMUNITY 


stored  in  the  cells.  Pollen  is  gathered  from  flowers  and 
carried  on  the  hind  legs  in  pollen  baskets,  which  are  concave 
segments  fringed  with  hairs.  From  this  pollen,  bee  bread 
is  made,  which  is  fed  to  the  larvae. 

Flowers  visited  by  bees.  The  first  requisite  for  success- 
ful beekeeping  is  the  presence,  within  a  radius  of  a  mile, 
of  proper  kinds  of  flowers  from  which  nectar  and  pollen  may 
be  gathered.  Hives  may  be  kept  even  on  roofs  in  cities, 
if  parks  and  the  right  kind  of  shade  trees  are  near.  Of  the 
trees  commonly  planted  along  the  streets,  the  red  maple, 
tulip,  locust,  horse  chestnut,  and  linden  invite  the  bees, 


FIG.  80.  —  Below,  an  empty  section  holder ;  above,  one  fitted  with  section-boxes,  in 
which  are  foundation  starters ;   two  of  these  have  been  added  to  by  the  bees. 

—  especially  the  linden,  which  is  one  of  the  very  best  of  all 
honey-producing  plants.  Other  valuable  flowers  are  those 
of  fruit  trees,  clover,  buckwheat,  raspberry,  and  of  many 
wild  flowers,  such  as  the  sweet  clover  and  goldenrod.  The 
blossoms  of  many  plants  in  both  the  vegetable  and  flower 
gardens  are  visited  by  bees. 

Annual  yield.  A  colony  of  bees  may  be  expected  to  yield 
annually  an  average  of  from  25  to  30  pounds  of  comb  honey, 
or  40  to  50  pounds  of  extracted  honey.  In  the  former  case 
the  comb  in  which  the  honey  is  stored  in  the  hive  is  taken 


POULTRY  KEEPING  AND   BEEKEEPING 


223 


with  the  honey.  In  the  latter  case  the  liquid  honey  is 
extracted  from  the  combs  by  means  of  a  centrifugal  machine. 
How  to  begin.  Spring  is  the  best  time  of  the  year  to 
begin  beekeeping.  It  is  best  for  the  inexperienced  bee- 
keeper to  procure 
from  some  reliable 
dealer  a  first-class 
colony  of  Italian 
or  Carniolan  bees 
in  a  good  frame 
hive.  The  cost 
will  be  from  $10.00 
to  $20.00.  While 
bees  can  be  se- 
cured at  less  cost, 
in  the  end  the  bet- 


FIG.  81. — A  section-box  filled  with  honey. 


ter  equipment  will 
prove  more  satis- 
factory.    If  one  begins  in  the  spring,  there  is  the  probability 
of  an  opportunity  to  increase  the  number  of  colonies  through 

swarming.  If  they  are 
watched,  they  may  usu- 
ally be  induced  to  occupy 
another  hive  by  proper 
handling.  This  swarm- 
ing takes  place  in  May 
and  June. 

The  hive.  A  hive  con- 
sists of  two  parts.  The 
lower  portion,  known  as 
the  brood  chamber,  con- 

FiG.  82.  —  One  and  a  half  story  hive  for  comb- 
honey  ;  the  super  is  filled  with  section-boxes. 


tains  the  brood  combs,  in 
which  the  young  bees  are 


reared.     The  upper  story  is  the  super,  in  which  are  placed 
sections  where  the  excess  honey  is  stored.     When  these  are 


224 


SCIENCE  OF  HOME  AND   COMMUNITY 


filled  (see  figure  81)  they  are  sold  as  gpmb  honey  and  re- 
placed by  other  empty  sections  (see  figure  80)  or  the  honey 
may  be  extracted  and  the  same  section  replaced.  The  hives 
should  be  placed  where  they  are  partially  shaded.  If  no 
shade  trees  are  near,  artificial  shade  may  be  provided  by 
erecting  a  wooden  roof  over  the  hives. 

Wintering  bees.  The  simplest  way  to  winter  bees  is  to 
use  a  chafl  hive  and  allow  them  to  remain  outdoors.  This 
hive  has  double  walls  separated  by  a  few  inches,  the  inter- 


'A  '^  £  0 

FIG.  83.  —  Appliances  for  keeping  bees:   A,  bee-escape;   B,  veil;   C,  smoker. 

vening  space  being  filled  with  chaff  or  similar  material. 
This  tends  to  keep  the  hive  warm  in  winter  and  cool  in  sum- 
mer. The  bees  must  also  have  sufficient  honey  or  sirup 
stored  in  the  combs  to  furnish  them  food  during  the  winter. 
In  the  most  northern  states,  however,  the  bees  must  be 
wintered  indoors. 

Kinds  of  bees  to  choose.  With  the  improved  strains  of 
bees  now  used  and  with  modern  appliances  there  is  very 
little  chance  of  being  stung  while  working  with  bees.  The 
nervous  and  warlike  black  bees,  which  were  formerly  kept, 
have  now  been  largely  replaced  by  the  much  gentler  Italians 
and  Carniolans.  So  gentle  are  these  that  many  beekeepers 
never  use  any  protection  while  handling  them.  But  one 


POULTRY    KEEPING   AND   BEEKEEPING  225 

may  handle  any  bees  with  no  danger  of  being  stung  if  he  is 
provided  with  bee-gloves,  veil,  and  smoker. 

One  of  the  returns  from  beekeeping  is  the  opportunity 
afforded  to  study  the  interesting  life  of  bees.  This  is  even 
greater  if  an  observation  hive  is  used,  which  contains  panes 
of  glass  set  in  the  side,  through  which  the  activities  of  the 
bees  may  be  watched.  A  door  is  arranged  to  cover  this 
glass  when  the  interior  is  not  under  inspection. 

SUPPLEMENTARY  QUESTIONS  FOR  CLASS  DISCUSSION 

1 .  What  care  do  poultry  require  ? 

2.  Which  require  more  care,  bees  or  poultry? 

3.  Which  is  more  interesting,   keeping  poultry  or  keeping 
bees? 

4.  Which  is  better  adapted  to  a  small  yard  ? 

5.  What  habits  of  bees  make  them  interesting  to  watch? 

REFERENCES 

Maynard,  The  Small  Country  Place,  J.  B.  Lippincott  Co.,  Phila- 
delphia. 

Valentine,  How  to  Keep  Hens  for  Profit,  Macmillan  Co.,  New 
York  City. 

Comstock,  How  to  Keep  Bees,  Doubleday  Page  Co.,  New  York 
City. 


CHAPTER  XV 
ATTRACTING  BIRDS  AROUND   THE   HOME 

1.  Why  is  it  desirable  to  have  birds  about  the 
home? 

2.  What  may  be  done  to  attract  them  there? 

One  thing  that  helps  to  make  the  home  attractive  is  the 
presence  of  birds  in  the  trees  and  on  the  lawn.  If  the  con- 
ditions are  favorable,  some  birds  will  come  to  the  yard  with- 
out effort  011  our  part ;  but  it  is  possible  to  increase  very 
largely  the  number  of  birds  around  our  homes  by  offering 
special  inducements. 

Reasons  for  attracting  birds.  There  are  two  reasons 
why  it  is  desirable  to  attract  birds  to  our  houses :  first,  be- 
cause of  the  pleasure  which  they  give  on  account  of  their 
attractive  colors,  pleasing  songs,  and  interesting  nesting 
habits;  and  second,  because  the  birds  will  help  destroy 
the  injurious  insects  that  attack  the  plants  of  the  garden. 
The  food  of  birds  consists  largely  of  insects,  and  if  the  birds 
are  nesting  in  our  yards,  they  will  obtain  these  insects  chiefly 
from  the  plants  found  growing  there. 

Bird  music.  Bird  songs  are  attractive  on  account  of  their 
great  variety  and  the  melody  of  their  tones.  Some  songs 
consist  of  a  few  simple,  unmusical  syllables,  which  so  strongly 
resemble  certain  words  that  the  birds  have  been  named 
from  them:  such  as  the  chickadee  and  bob  white.  On  the 
other  hand,  some  birds  are  wonderful  songsters,  and  it  is 
worth  while  to  make  an  effort  to  hear  them,  just  as  one  plans 
to  attend  a  concert  to  hear  a  wonderful  musician.  Some 

226 


ATTRACTING  BIRDS  AROUND  THE  HOME  227 

of  the  birds  which  deserve  special  mention  on  account  of 
the  pleasing  character  of  their  songs  are  the  house  wren, 
the  brown  thrasher,  the  goldfinch,  the  song  sparrow,  the 
wood  thrush,  and  the  hermit  thrush.  Most  bird  students 
agree  that  the  thrushes  are  the  best  songsters. 

Spring  is  the  season  of  bird  song.  The  chorus  begins  in 
the  early  spring  when  the  first  birds  return,  and  the  climax 
is  reached  about  the  middle  of  May;  and  then  the  birds 
gradually  stop  singing  so  that  the  season  is  nearly  over  by 
the  first  of  July. 

The  birds  begin  to  sing  at  the  earliest  daybreak  and  the 
climax  is  reached  at  about  sunrise ;  then  the  singing  grad- 
ually becomes  less  till  the  morning  chorus  is  over  by  the 
middle  of  the  forenoon.  There  is  another  shorter  period 
of  singing  in  the  late  afternoon  shortly  before  sunset. 

FIELD  EXERCISE  4 

Purpose.  To  see  how  many  birds  you  can  recognize  from 
their  songs.  . 

Directions.  I .  Some  morning  in  May  is  the  best  time  to  study 
bird  songs.  Notice  how  the  songs  of  birds  differ.  Which  ones 
are  especially  musical  ?  See  how  many  birds  you  can  recognize 
from  the  songs. 

2.  Note  some  of  the  following  points   for   each  song:  (a) 
whether  varied  or  monotonous,  (b)  loud  or  soft,  (c)  high  or  low 
pitch,  (d)  musical  or  unmusical. 

3.  Write  the  names  of  all  the  birds  whose  songs  you  know  in 
the  order  of  their  •  attractiveness,   putting  the  most  pleasing 
first  and  the  least  pleasing  last. 

Nesting  habits.  The  nesting  habits  of  birds  are  so  inter- 
esting that  it  is  a  pleasure  to  have  birds  around  our  home. 
The  nests  themselves  are  made  of  a  great  variety  of  materials 
and  are  found  in  a  great  variety  of  locations,  on  the  ground, 
in  bushes,  in  trees,  in  barns,  and  even  in  chimneys.  It  is 
interesting  to  notice  the  method  by  which  birds  build  and 


228 


SCIENCE  OF  HOME  AND   COMMUNITY 


shape  their  nests.  The  Baltimore  oriole  weaves  its  nest 
with  its  bill;  the  robin  uses  its  breast  to  mold  the  shape 
of  the  nest. 

Usually  from  three  to  six  eggs  are  laid  in  the  nest,  and 
these  hatch  in  about  two  weeks  in  the  case  of  most  bf  our 
common  birds.  The  period  that  follows  the  hatching  of  the 
young  is  a  most  interesting  time.  One  of  the  most  remark- 
able features  about  the  rearing  of  the  young  is  the  fre- 
quency of  feeding.  It  is  worth  while  to  watch  a  nest  for  an 
hour  and  see  how  many  times  the  young  are  fed.  Another 

interesting  feature  is 
to  watch  the  parent 
birds  teach  the  young 
birds  how  to  fly  and  to 
feed  themselves  after 
they  leave  the  nest. 

The  cowbird  has 
the  peculiar  habit  of 
laying  her  eggs  in  the 
nests  of  other  birds. 
When  these  hatch 
they  are  reared  by 

the  foster  mother  the 

same  as  her  own 
young.  It  is  a  curious  sight  to  see  a  little  mother  feeding  a 
young  cowbird  bigger  than  herself.  (See  figure  84.) 

Four  things  may  be  done  to  attract  birds :  first,  provide 
nesting  boxes;  second,  feed  the  winter  birds;  third,  pro- 
vide fountains  for  drinking  and  bathing;  and  fourth,  plant 
shrubs  which  bear  fruit  that  is  eaten  by  birds.  The  first 
is  done  in  the  spring,  the  third  in  the  summer,  and  the  second 
in  the  winter,  so  something  can  be  done  in  almost  every 
season  of  the  year. 

Providing  nesting  boxes.  Some  kinds  of  birds  will  build 
their  nests  in  artificial  nesting  boxes  put  out  for  them. 


FIG.  84. — Redstart  feeding  young  cowbird. 


ATTRACTING  BIRDS  AROUND  THE  HOME  2 29 

r 

Whether  any  particular  bird  will  clo  this  depends  on  its 
natural  nesting  site ;  if  it  nests  in  a  hollow  limb,  there  is  a 
possibility  that  it  may  use  a  nesting  box.  A  great  many 
kinds  of  birds  have  been  known  to  occupy  these  houses.  The 
author  has  been  able  to  list  twenty-nine  kinds  of  birds  which 
have  positively  been  known  to  use  these  boxes  somewhere 
in  the  United  States.  The  kinds  which  use  them  most 
commonly  are  the  bluebirds,  wrens,  martins,  tree  swallows, 
and  flickers.  The  martins  have  now  become  so  accustomed 
to  these  artificial  houses  that  they  seldom  nest  anywhere 
else. 

Houses  to  suit  the  birds.  A  great  variety  of  houses  can 
be  made,  all  of  which  will  attract  birds.  Wood  is  most 
commonly  used.  This  may  be  ordinary  boards  or  old 
weather-beaten  boards.  If  new  boards  are  used,  they 
should  be  painted  or  stained  green  or  brown,  or  else  rubbed 
in  mud  so  as  to  take  off  the  new  look.  Pieces  of  slabs  with 
the  bark  on  make  good  material.  Sometimes  sections  of 
hollow  limbs  may  be  found  in  the  woods,  or  sections  of 
small  trees  may  be  cut  and  the  center  hollowed  out  with 
augur  or  chisel.  Tin  cans,  roofing  paper,  pottery,  cement, 
and  gourds  may  also  be  used. 

The  houses  are  made  in  a  great  variety  of  shapes.  Some- 
times attempts  are  made  to  imitate  man's  houses,  but  the 
ordinary  box  shape  is  probably  as  good  as  any.  The  size 
of  the  house  depends  on  the  bird  that  is  to  occupy  it. 

Birds  may  be  conveniently  classed  in  three  groups  accord- 
ing to  the  size  of  the  house  and  entrance  hole  needed,  as 
small,  medium,  and  large.  To  the  small  group  belong  such 
birds  as  the  wren  and  chickadee,  which  can  use  a  hole  too 
srnall  for  the  English  sparrow.  To  the  medium  group  be- 
long such  birds  as  the  bluebird  and  the  tree  swallow,  which 
can  use  a  hole  too  small  for  the  starling.  To  the  large  group 
belong  such  birds  as  the  flicker  and  red-headed  woodpecker, 
which  require  an  entrance  of  from  two  to  three  inches. 


230  SCIENCE  OF  HOME  AND   COMMUNITY 


FIG.  85.  —  Three  types  of  nesting  boxes. 


The  following  table  gives  a  few  essential  points  regarding 
the  size  of  bird  houses. 


NAME  OF  BIRD 

DIAMETER  OF 
ENTRANCE  HOLE 

FLOOR 

HEIGHT 

Wren     .... 

I     inch 

4  inches  square 

6-8    inches 

Bluebird     .     .     . 

i  \  inches 

5-6  inches  square 

10-12  inches 

Tree  swallow  . 

\\  inches 

5—6  inches  square 

10-12  inches 

Flicker  .... 

2§  inches 

6-8  inches  square 

1  2-  1  8  inches 

Bluebird.  Below  are  given  directions  for  building  a  house 
for  a  bluebird.  This  house  seems  to  be  the  best  type, 
although  other  types  are  frequently  used  by  birds.  The 
long  dimension  of  the  house  should  run  up  and  down  ver- 
tically. For  the  floor  use  a  piece  of  board  6  inches  square, 
for  the  back  a  piece  12  inches  long,  for  the  front  a  piece 
10  inches  long,  and  for  the  sides  two  pieces  i  i-J  inches  long 
on  one  edge  and  p-J  inches  long  on  the  other  edge.  When 


ATTRACTING  BIRDS  AROUND  THE  HOME  231 

these  sides  are  nailed  to  the  front  and  back,  a  space  of  -J  inch 
is  left  at  the  top  for  ventilation.  For  the  roof  use  a  piece 
9  inches  long,  so  that  it  will  project  well  out  over  the  en- 
trance. This  roof  should  be  fastened  at  the  back  with 
hinges  and  in  front  with  a  clasp.  The  entrance  hole  should 
be  one  and  a  half  inches  in  diameter  and  should  be  bored 
in  the  front  (the  ic-inch  board)  2  inches  from  the  top.  No 
perch  should  be  provided. 

The  reasons  for  building  the  house  this  way  are  these. 
The  purpose  of  having  the  long  axis  vertical,  of  having  the 
hole  near  the  top,  and  of  having  the  overhanging  roof,  is  to 
protect  the  young  birds  from  cats.  Cats  climb  up  to  boxes 
and  try  to  claw  out  the  young  birds  by  reaching  down 
through  the  hole.  In  this  type  of  house,  it  is  almost  im- 
possible for  a  cat  to  reach  down  to  the  young  birds.  More- 
over, this  style  of  house  prevents  the  young  from  leaving 
the  house  till  they  are  well  matured,  and  better  able  to 
care  for  themselves  and  to  escape  such  enemies  as  cats  and 
squirrels.  If  the  hole  is  too  low  down,  the  young  birds  may 
fall  out  before  they  are  old  enough  to  leave  the  nest.  The 
house  should  be  made  with  a  movable  roof,  so  that  each 
spring  all  the  material  in  the  house  may  be  cleaned  out,  and 
in  case  English  sparrows  begin  to  use  the  house,  their  eggs 
may  be  removed.  The  perch  is  omitted  because  the  native 
birds  do  not  need  it,  and  it  furnishes  an  opportunity  for  the 
English  sparrow  to  stand  and  fight  the  birds  that  are  using 
the  house,  even  when  the  hole  is  too  small  for  the  sparrow 
to  enter. 

House  wren.  The  house  wren  will  use  a  great  variety  of 
boxes.  The  entrance  should  be  i  inch  in  diameter.  A  very 
satisfactory  house  can  be  made  from  an  old  tomato  can. 
In  the  open  end  is  fastened  a  circular  piece  of  wood  with  an 
opening  of  i  inch  in  the  upper  third.  The  author  kept  one 
of  these  houses  in  his  yard  for  four  successive  seasons,  during 
which  time  five  broods  of  wrens  were  reared  in  it. 


232 


SCIENCE  OF  HOME  AND   COMMUNITY 


Martin.  While  most  birds  prefer  a  house  with  a  single 
apartment,  the  martins  prefer  to  live  together  in  colonies; 
so  that  for  them  houses  are  made  with  a  number  of  rooms. 
Each  dimension  of  the  room  should  be  6  to  7  inches.  The 

opening  should  be 
about  2-J  inches 
across. 

Putting  out  the 
house.  In  putting 
out  the  house  one 
needs  to  consider  five 
things:  the  time,  the 
location,  the  height, 
the  method  of  fasten- 
ing, and  the  protec- 
tion from  enemies. 
The  house  should  be 
put  out  early  in  the 
spring  just  before  the 
bird  is  expected  to  re- 
turn.  Bluebirds 
and  wrens  both  rear 
two  broods  ;  so  that 
houses  put  out  in  the 
late  spring  may  be 
in  time  for  the  second 
brood. 

Houses  should  be  placed  out  in  the  open,  for  birds  will 
not  use  them  so  frequently  if  they  are  placed  in  the  dense 
shade.  Telephone  poles  and  grape  arbors  make  good 
situations.  Houses  may  also  be  placed  on  trees  if  they 
stand  out  by  themselves,  separate  from  other  trees.  The 
best  height  for  the  house  is  8  to  15  feet.  The  house  should 
be  fastened  so  that  it  is  secure  against  the  winds,  but  so 
that  it  can  be  easily  taken  down  and  cleaned.  Some  have  a 


FIG.  86.  —  A  martin  h^u 


ATTRACTING  BIRDS  AROUND  THE  HOME 


233 


screw  eye,  a  loop  of  wire,  or  hole  in  the  back,  which  can  be 
placed  over  a  hook;  some  have  an  extension  of  the  back 
by  means  of  which  it  can  be  screwed  or  nailed  up ;  and  others 
are  suspended  by  wire  so  as  to  swing  in  the  wind. 

Protection  from  cats.  Two  enemies  of  our  birds  are  un- 
fortunately very  common,  the  cat  and  the  English  sparrow. 
The  birds  can  be  protected  from  the  cat  to  some  extent  in 


FIG.  87.  —  Open  nesting  boxes. 

the  construction  of  the  house,  as  already  explained.  Still 
further  protection  may  be  given  when  the  house  is  put  up. 
A  piece  of  zinc  or  tin  about  2  feet  wide  may  be  wrapped 
around  the  tree  or  post  4  feet  from  the  ground  and  fastened. 
Another  method  of  protection  is  to  fasten  the  boxes  to  the 
top  of  posts  by  means  of  iron  bands  two  feet  long. 

Protection  from  English  sparrows.  The  wren  may  be 
protected  against  the  English  sparrow  by  making  the  hole 
so  small  (i  inch)  that  the  sparrow  cannot  enter.  In  the 


234  SCIENCE  OF  HOME  AND   COMMUNITY 

case  of  houses  for  the  bluebird,  which  have  a  hole  large 
enough  for  the  sparrow,  the  best  thing  to  do  is  to  make  the 
house  with  a  movable  cover  and  remove  the  sparrow's  eggs 
about  once  a  week.  Oftentimes  this  will  drive  sparrows 
away. 

Open  houses.  Other  birds  which  do  not  nest  in  cavities 
will  sometimes  build  their  nests  in  a  box,  open  on  three  sides 
like  a  porch.  (See  figure  87.)  These  houses  consist  of  a  floor 
from  6  to  8  inches  square  with  a  roof  held  up  by  posts  at  the 
corners,  or  the  back  may  be  a  solid  board,  leaving  three 
sides  open.  Birds  which  have  been  known  to  occupy  these 
houses  are  the  robin,  phcebe,  song  sparrow,  and  catbird. 
These  houses  should  be  put  up  in  locations  where  these 
birds  usually  nest. 

All  types  of  houses  referred  to  can  be  easily  made  with 
the  simplest  tools ;  but  if  one  wishes  to  buy  these  houses  they 
can  be  procured  from  various  dealers  at  prices  ranging  from 
50  cents  to  2  dollars  apiece. 

LABORATORY  EXERCISE  25 

Purpose.     To  study  some  types  of  bird  houses. 

Apparatus.  Collection  of  types  of  bird  houses  showing 
adaptations  to  different  birds. 

Directions,  i.  For  each  house  studied  notice  (a)  size, 
(&)  shape,  (c)  size  and  location  of  entrance  hole,  (d)  means  of 
fastening.  Make  a  drawing  of  each  box. 

2.  Taking  the  boxes  together  as  a  group,  notice  the  chief 
differences.  Are  there  any  respects  in  which  all  agree  ?  Which 
do  you  consider  the  best  house  ?  Why  ? 

HOME  PROJECT  26 

Purpose.     To  make  a  nesting  house  to  put  in  your  home  yard. 

Directions.  I .  Find  out  which  birds  that  use  nesting  boxes 
are  most  common  around  your  home,  and  make  a  nesting  box  for 
them.  Look  up  some  bird  books  so  as  to  find  the  kind  of 


ATTRACTING  BIRDS  AROUND  THE  HOME  235 

house  best  adapted  for  this  particular  bird.      Then  put  it  up 
in  the  most  suitable  place  in  your  yard. 

2.  If  the  house  is  occupied,  the  following  observations  may 
be  made :  bird  using  box,  date  nest  begun,  date  young  hatched, 
date  young  left  nest,  number  of  times  young  fed  in  an  hour, 
time  of  day  birds  begin  to  feed  young,  time  of  last  feeding, 
kind  of  food  brought,  division  of  work  between  father  and 
mother. 

SCHOOL  PROJECT  7 

Purpose.     To  put  up  nesting  boxes  in  the  school  yard. 

Directions.  If  the  schoolhouse  is  so  located  that  birds  are 
found  there,  and  if  there  are  good  opportunities  for  putting  up 
bird  houses,  the  class  may  arrange  to  build  a  few  houses  and 
put  them  on  the  school  ground. 

Providing  nesting  material.  Still  other  birds  may  be 
attracted  around  our  homes  by  putting  out  materials  that 
birds  use  in  making  their  nests.  Among  the  best  materials 
to  put  out  are  yarns  (in  pieces  about  a  foot  long),  strings, 
horsehair,  small  strips  of  cloth,  cotton  batting,  and  shoe- 
maker's flax.  Such  birds  as  the  oriole,  chipping  sparrow, 
robin,  and  others  may  use  them. 

Feeding  winter  birds.  During  the  winter  when  snow 
covers  the  ground,  it  is  difficult  for  birds  to  obtain  food. 
If  food  is  placed  out  for  these  birds,  they  will  come  very 
close  to  the  house,  even  to  the  window  sill,  where  they  can 
be  watched  from  just  inside  the  window.  Among  the  more 
common, birds  which  come  around  the  house  to  feed  are  the 
woodpeckers,  the  chickadee,  the  nuthatch,  the  bluejay, 
the  junco,  and  tree  sparrow.  These  birds,  especially  the 
chickadee,  often  become  sufficiently  tame  to  feed  from  the 
hand. 

Kinds  of  food.  Birds  may  be  divided  into  two  groups 
according  to  their  food,  into  seed-eating  and  insect-eating 
birds,  although  many  eat  both  seeds  and  insects.  The  best 


236 


SCIENCE  OF  HOME  AND   COMMUNITY 


•lllliBlllffeiriiiiiM'jf 

II  '>  Hi  ill  ill!  i  ammiiB 


food  for  the  insect-eating  bird  is  suet.  The  best  foods  for 
the  seed-eating  birds  are  sunflower  seeds,  hemp,  millet,  nuts, 
grains,  and  crumbs. 

Methods  of  offering  the  food.     Food  may  be  put  out  in  a 
great  variety  of  ways :  on  the  ground,  on  shelves,  in  suet 

baskets,  in  automatic 


hoppers,  on  a  moving 
counter,  or  in  Audu- 
bon  and  weathercock 
food  houses.  One  of 
the  simplest  ways  to 
put  food  out  is  to 
trample  down  a  spot 
in  the  snow  and  scat- 
ter out  crumbs  and 
grains. 

Various  kinds  of 
shelves  may  be  used. 
They  may  consist 
simply  of  a  board, 
with  a  narrow  strip 

around  the  edge,  which  may  be  fastened  to  a  tree  or  post,  or 
be  placed  on  the  window  sill.  A  suet  box  can  easily  be  made. 
A  piece  of  board  5  or  6  inches  square  serves  as  the  back. 
Around  two  sides  and  the  bottom  of  this  are  nailed  strips 
about  i-J  inches  wide.  Over  this  is  fastened  a  piece  of  hard- 
ware cloth  or  of  poultry  netting  with  small  meshes.  This 
may  be  suspended  by  means  of  a  screw  eye  at  the  top.  Suet 
may  also  be  fastened  on  a  branch  by  tying  a  string  around  it. 
Automatic  feeders  on  the  principle  of  poultry  hoppers 
can  be  bought  or  easily  made.  (See  figure  89.)  The  large 
hopper  is  filled  with  seeds  and  grain,  which  come  out  of 
a  small  opening  at  the  bottom  leading  to  a  shelf.  As 
fast  as  the  seeds  are  eaten,  others  fall  down  to  take  their 
•place. 


FIG.  88.  —  Suet  baskets. 


ATTRACTING  BIRDS  AROUND   THE  HOME 


237 


A  moving  counter  may  be  arranged  on  a  pulley  running 
on  a  wire,  which  may  be  fastened  between  a  second  story 
window  and  a  neighboring  tree. 
A  string  may  be  fastened  to  this 
so  that  it  can  be  kept  in  any  posi- 
tion desired. 

Dealers  in  bird  appliances  sell 
what  are  known  as  the  weathercock 
and  the  Audubon  food  houses. 
The  first  is  a  box  open  on  one  side 
and  placed  on  a  pivot  so  that  it 
swings  with  the  wind,  keeping  the 
open  side  away  from  the  wind  and 
thus  protecting  the  birds.  The 
Audubon  food  house  has  panes  of 
glass  around  the  sides  to  protect 
thp  birds  from  storms  and  an  en- 


FIG.  89.  —  Bird  feeder. 


trance  from  underneath  by  which  the  birds  come  to  the  food 
placed  behind  the  glass. 

HOME  PROJECT  27 

Purpose.     To  feed  the  winter  birds. 

Directions.  I.  If  winter  birds  are  found  around  your  home, 
begin  in  the  late  fall  to  provide  them  with  food.  A  suet  box, 
as  explained  in  this  chapter,  can  be  easily  made,  also  a  feedery 
can  be  made  out  of  wood  similar  to  the  automatic  hoppers  used 
for  poultry.  See  that  these  devices  are  kept  constantly  sup- 
plied with  food. 

2.  Interesting  studies  of  the  birds  that  come  to  feed  may  be 
made  in  accordance  with  the  following  outline. 


NAME  or 
BIRD 

FOODS 
EATEN 

FOODS 
PREFERRED 

METHOD  OF 
APPROACHING 
FOOD 

CALL 
NOTES 

DEGREE  OF 
TAUENESS 

238  SCIENCE   OF   HOME   AND    COMMUNITY 

Bird  fountains.  Birds  use  water  for  two  purposes:  for 
drinking  and  for  bathing.  In  constructing  a  fountain,  two 
things  should  be  kept  in  mind :  first,  the  edge  and  bottom 
should  be  made  of  roughened  material,  so  that  the  bird  wilt 
not  slip;  second,  the  water  should  be  shallow,  not  exceed- 
ing three  inches.  Simple  bird  baths  may  be  made  of  such 
receptacles  as  large  flowerpot  saucers  and  ordinary  pans. 

The  fountain  should  be  placed  in  such  a  location  that  no 
cats  can  lurk  near  in  shrubbery  to  jump  out  at  the  birds. 
The  fountain  may  be  raised  on  a  pedestal. 

One  of  the  most  successful  types  of  fountain  is  made  of 
cement  and  sunk  in  the  ground.  A  hole  about  3  feet  across 
is  dug  out,  gradually  sloping  from  the  edge  to  a  depth  of 
about  5  inches  in  the  center.  This  is  plastered  over  with  a 
mixture  of  Portland  cement  and  sand,  thick  enough  to  leave 
the  center  3  inches  deep  and  slope  gradually  from  there  to 
the  edge.  If  it  is  impossible  to  supply  running  water,  these 
fountains  may  be  cleaned  out  once  a  week  with  a  broom  and 
new  water  added. 

HOME  PROJECT  28 

Purpose.     To  provide  water  for  the  birds. 

Directions.  If  there  are  no  opportunities  for  birds  to  find 
water  around  your  yard,  a  fountain  may  be  the  means  of  at- 
tracting many  birds  that  you  will  enjoy  watching.  This  will 
afford  opportunity  to  see  birds  during  the  summer  when  they 
are  quiet  and  retiring.  As  already  explained  in  this  chapter, 
very  simple  devices,  such  as  ordinary  pans,  may  be  used.  The 
water  should  be  changed  occasionally  so  as  to  keep  it  clean  and 
cool. 

Planting  shrubs  for  the  birds.  Shrubs  furnish  nesting 
sites  for  birds,  and  many  bear  fruit  which  the  birds  eat. 
In  planning  the  home  grounds,  some  shrubs  may  be  used 
which  bear  these  fruits ;  and  as  some  hold  their  fruit  during 
the  winter,  they  serve  too  as  a  means  of  ornamentation. 
The  birds  which  feed  largely  upon  wild  fruit  are  the  cedar 


ATTRACTING  BIRDS  AROUND   THE  HOME  239 

waxwing,  robin,  catbird,  fox  sparrow,  flicker,  grosbeak, 
and  bluebird ;  and  there  are  a  number  of  others  which  feed 
to  a  lesser  extent  on  wild  fruit.  The  fruits  most  commonly 
eaten  are  those  of  the  elder,  mulberry,  dogwood,  wild  cherries, 
bayberry,  and  Juneberry.  The  mulberry  is  one  of  the  best 
plants  to  set  out  and  this  serves  as  a  protection  to  cultivated 
fruit,  as  some  birds  eat  the  mulberry  in  preference  to  culti- 
vated fruit  that  may  be  growing  near. 

Domestication  of  wild  birds.  Considerable  progress  has 
been  made  in  recent  years  in  the  domestication  of  wild  birds. 
The  greatest  success  has  been  achieved  in  rearing  the  mallard 
duck,  bobwhite,  and  pheasant.  Some  strains  of  the  mallard 
duck  have  been  thoroughly  domesticated  and  the  rearing 
and  selling  of  these  birds  is  coming  to  be  an  industry  some- 
what similar  to  poultry  raising.  In  many  states  there  are 
game  farms  on  which  wild  birds  are  reared. 

SUPPLEMENTARY  QUESTIONS  FOR  CLASS  DISCUSSION 

1.  What  things  must  one  take  into  account  in  building  a 
bird  house  ? 

2.  Which  is  the  best  type  of  house? 

3.  How  should  a  house  be  put  out  ? 

4.  How  may  birds  be  protected  from  the  cat  and  from  the 
English  sparrow? 

5.  Which  method  of  attracting  birds  will  give  the  greatest 
pleasure  ? 

6.  Which  is  the  best  way  of  putting  out  food  for  the  winter 
birds  ? 

7.  What  should  one  consider  in  making  a  bird  fountain? 

8.  What  benefit  will  the  birds  derive  from  the  things  we  can 
do  to  attract  them  around  our  homes  ? 

REFERENCES 

Baynes,  Wild  Bird  Guests,  E.  P.  Button  Co.,  New  York  City. 
Trafton,  Bird  Friends,  Houghton  Mifflin  Co.,  Boston.     Chaps. 
19-22. 


PART   II 
SCIENCE  OF  THE   COMMUNITY 


241 


PART  II 

SCIENCE   OF  THE   COMMUNITY 


241 


SECTION  A 
MEANS  OF  TRAVEL 

CHAPTER  XVI 

• 

THE  LOCOMOTIVE 

1.  What  part  do  locomotives  play  in  the  life  of 
the  community? 

2.  How  is  a  locomotive  constructed  and  how 
does  it  work  ? 

Travel  in  early  days.  When  the  white  settlers  first  came 
to  this  country,  there  was  no  need  nor  any  means  of  travel 
outside  of  their  little  village.  Later,  horses  were  brought 
over  from  England,  and,  as  different  colonies  were  established, 
travel  by  horseback  became  common.  Still  later  the  paths 
were  widened  to  roads,  and  the  stagecoach  became  the 
means  of  fast  travel.  Finally  this  was  replaced  by  the 
locomotive. 

Uses  of  locomotive.  The  locomotive  plays  a  very  im- 
portant part  in  our  daily  life.  Not  only  does  it  enable  us 
to  travel  quickly  and  comfortably  from  one  place  to  another, 
but  it  brings  to*  us  most  of  the  necessities  of  our  daily  life. 
Many  of  our  foods  are  brought  from  long  distances  by  means 
of  the  locomotive.  Oranges  are  brought  from  California, 
early  strawberries  from  Florida,  sugar  from  the  southern 
states,  flour  from  the  flour  mills  of  Minneapolis,  meat  from 
the  stock  yards  of  Chicago.  If  we  should  make  a  complete 
list  of  all  the  kinds  of  foods  we  eat,  we  should  find  that  the 

243 


244  SCIENCE  OF  HOME  AND    COMMUNITY 

great  majority,  excepting  a  few  fruits  and  vegetables  raised 
locally  near  our  towns,  have  been  brought  to  us  in  some 
part  of  their  journey  by  means  of  the  locomotive. 

It  is  the  same  with  reference  to  our  clothing.  The  wool, 
after  being  sheared  from  the  sheep,  was  first  taken  by  loco- 
motives to  factories,  where  it  was  spun  into  cloth;  it  was 
then  taken  again  by  locomotives  and  carried  to  other  facto- 
ries, where  it  was  made  into  clothing ;  then  brought  to  our 
town,  where  we  finally  bought  it.  Our  cotton  clothing  was 
made  from  cotton  which  was  carried  from  the  cotton  fields 
in  the  south  to  the  mills  by  the  locomotive.  It  was  made 
into  cloth,  and  then  taken  to  factories  where  it  was  made 
into  various  articles  which  were  brought  to  the  store  and 
put  on  sale.  The  locomotive  played  an  important  part 
several  different  times  during  this  process. 

The  coal  that  keeps  us  warm  in  the  winter  has  been  brought 
to  us  from  the  coal  fields  by  the  locomotive.  The  news- 
papers, magazines,  and  books,  that  are  so  important  in  our 
life,  are  brought  to  us  by  the  locomotive.  On  the  payment 
of  two  cents  for  a  postage  stamp,  a  letter  is  carried  for  us 
across  the  continent  by  the  locomotive,  and  in  a  few  days 
an  answer  is  brought  back. 

Indeed  if  we  think  over  carefully  the  things  that  enter 
into  our  daily  life — the  house  in  which  we  live,  the  rugs  upon 
the  floor,  the  furnishings  inside,  the  piano,  the  phonograph, 
and  other  necessities  and  pleasures  of  life  —  we  shall  find 
it  difficult  to  name  anything  which  the  locomotive  has  not 
either  directly  or  indirectly  helped  bring  to  us. 

Locomotives  and  suburban  homes.  Another  benefit  of 
the  locomotive  lies  in  the  fact  that  it  has  increased  greatly 
the  distance  that  a  man  may  live  from  his  place  of  business 
in  the  great  cities.  In  great  centers  of  population,  like 
New  York  and  Chicago,  thousands  of  business  men  may  do 
their  business  in  these  cities  and  at  night  return  to  their 
homes,  miles  away  in  small  suburban  towns.  This  enables 


THE  LOCOMOTIVE  245 

a  man  to  combine  the  advantage  of  country  life  for  himself 
and  family  with  the  advantages  of  a  central  location  for  his 
business  office. 

Locomotives  and  growth  of  the  United  States.  The 
locomotive  has  had  a  tremendous  influence  on  the  develop- 
ment of  the  United  States.  As  we  think  of  the  vast  reaches 
of  plains  and  the  great  chains  of  mountains  extending  across 
our  country,  we  can  readily  appreciate  how  slow  must  have 
been  the  growth  of  the  country  without  the  aid  of  the  loco- 
motive. Many  parts  of  the  country  which  now  support  a 
prosperous  population  would  not  even  be  open  to  settlement 
had  it  not  been  for  the  locomotive. 

Locomotive  and  travel.  The  locomotive  has  made  travel 
easy  and  cheap,  so  that  while  a  century  ago  few  people 
traveled  beyond  the  confines  of  their  own  town,  to-day  it  is 
common  for  people  to  travel  over  all  parts  of  the  United 
States.  The  knowledge  gained  of  how  other  people  live 
has  a  broadening  influence  and  tends  to  produce  a  feeling 
of  toleration  for  others,  and  travel  thus  results  in  more 
harmonious  cooperation  between  different  sections  of  the 
country. 

History  of  steam  engine  and  locomotive.  The  steam 
engine  and  locomotive  play  so  important  a  part  in  our  lives 
to-day  that  it  is  difficult  to  see  how  we  could  get  along  with- 
out them;  and  yet  the  railroads  in  this  country  have  all 
been  developed  within  the  last  hundred  years.  It  will  be 
interesting  to  look  at  the  history  of  the  steam  engine  and 
locomotive  and  see  the  changes  through  which  they  passed 
while  developing  their  present  form. 

The  first  steam  engine  was  made  in  120  B.C.  by  Hero  of 
Alexandria  in  Egypt.  This  was  so  arranged  that  steam  in 
escaping  from  small  tubes  on  a  flask  caused  it  to  rotate  in 
much  the  same  way  that  a  lawn  sprinkler  revolves  when 
water  is  forced  from  it.  The  device  was  only  a  toy,  and  no 
useful  application  was  made  of  it. 


246  SCIENCE  OF  HOME  AND    COMMUNITY 

It  was  a  long  time  after  this,  about  1700  years,  before  any 
further  thought  was  given  to  the  principle  of  steam  engines. 
In  1629  an  Italian  named  Branca  described  an  engine  which 
was  driven  by  steam  driving  directly  against  paddles  on  a 
wheel,  something  like  a  water  wheel.  In  1663,  a  real  steam 
engine  was  built  in  England,  which  was  actually  made  useful 
in  lifting  water  from  the  mines.  About  seventeen  years 
after  this  the  first  safety  valve  was  invented. 

Newcomen' s  engine.  In  1705  Thomas  Newcomen  con- 
structed a  steam  engine  that  was  a  great  improvement  on 
anything  that  had  so  far  been  made.  It  consisted  of  a 
steam  boiler  and  a  cylinder  in  which  moved  a  piston  head. 
The  steam  forced  this  head  to  one  end  of  the  cylinder,  and 
then,  by  turning  a  valve  by  hand,  a  spray  of  cold  water  was 
led  into  the  cylinder.  This  condensed  the  steam  and  formed 
a  vacuum,  and  the  atmospheric  pressure  forced  the  head 
back.  Thus  the  pressure  of  the  steam  forced  the  piston 
head  in  one  direction  and  the  weight  of  the  air  forced  it 
back.  This  machine  had  to  be  watched  and  the  valves  turned 
at  the  end  of  every  stroke.  It  has  sometimes  been  called 
an  atmospheric  engine. 

James  Watt.  The  next  great  improvement  was  made  by 
James  Watt  during  the  latter  half  of  the  eighteenth  century. 
He  invented  a  device  by  which  the  motion  of  the  engine  ad- 
justed valves  automatically  in  such  a  way  that  the  steam 
was  taken  in  turn  to  each  end  of  the  cylinder,  so  that  the 
piston  head  was  moved  in  both  directions  by  steam  pressure 
instead  of  in  only  one  direction  as  in  the  Newcomen  engine. 
The  steam  engine  of  to-day  is  essentially  in  principle  the 
same  as  the  one  invented  by  James  Watt,  except  that  there 
is  now  being  used  for  some  purposes  a  different  type  of  engine 
called  the  turbine.  But  in  the  locomotive  the  Watt  type  of 
engine  is  still  used. 

First  locomotive.  The  first  locomotive  was  invented  by 
an  Englishman  named  George  Stephenson.  In  1814  he 


TH2  LCC3MOTIVE 


247 


made  a  successful  trip  hauling  coal  cars  at  the  rate  of  four 
miles  per  hour.  The  first  commercial  railroad  to  carry  pas- 
sengers and  freight  was  built  between  Stockton  and  Darling- 
ton, England;  and  on  the  day  of  its  opening,  in  1825,  the 


FIG.  90.  —  Watt  engine. 

engine  was  driven  at  th'e  rate  of  15  miles  an  hour.     From 
this  date  the  future  of  the  locomotive  was  assured. 

The  first  locomotive  was  used  in  this  country  in  1829. 
After  that  railroads  developed  very  rapidly  in  the  United 
States,  many  miles  being  built  each  year.  In  1849  the  first 
continuous  line  between  New  York  and  Boston  was  com- 
pleted. In  1869  the  first  line  connecting  the  Atlantic  and 
Pacific  coasts  was  finished,  and  now  the  railroads  form  a 


248  SCIENCE   OF  HOME  AND    COMMUNITY 

network  over  the  whole  country.  The  older  forms  of  travel, 
by  horseback  and  stagecoach,  have  gradually  become  of 
less  importance,  and  the  railroad  has  now  become  the  chief 
means  of  long  distance  travel. 

Having  learned  something  about  the  important  part 
that  the  locomotive  plays  in  everyday  life  and  something 
of  its  history,  let  us  now  study  a  modern  locomotive  to  see 
how  it  is  built  and  how  it  works. 

Parts  of  a  locomotive.  The  locomotive  consists  of  three 
essential  parts :  first,  the  fire  box  and  boiler,  that  generate 
power ;  second,  the  cylinders  and  their  valve  gear,  that  use 
the  power;  and  third,  the  wheels  on  which  the  locomotive 
moves. 


FIG.  91.  —  First  locomotive  in  United  States. 


Boiler  and  fire  box.  The  purpose  of  the  fire  box  and  boiler 
is  to  convert  large  amounts  of  water  into  steam  in  a  short 
time.  In  order  to  do  this,  there  must  be  a  large  amount  of 
heating  surface,  with  heat  on  one  side  and  water  on  the  other, 
so  that  large  quantities  of  water  will  be  in  contact  with  the 
heated  surfaces.  There  is  a  direct  heating  surface  on  the 
boiler  immediately  over  the  fire  box,  and  in  addition  to  this 
there  is  the  indirect  heating  surface  made  by  using  small 
tubes  about  two  inches  in  diameter,  to  carry  off  the  heated 
gases  from  the  fire  box  to  the  smokestack.  About  200  of 
these  tubes  run  through  the  boiler  and  are  surrounded  with 
water.  By  means  of  these  tubes  a  heating  surface  of  2500 
square  feet  may  be  obtained,  that  is,  equal  to  an  area  50  feet 
square. 


THE   LOCOMOTIVE 


249 


Water  gauge.  The  boiler  has  attached  to  it  a  water  gauge, 
a  steam  gauge,  a  safety  valve,  and  an  injector.  The  water 
gauge  is  a  glass  tube  placed  on  the  outside  of  the  boiler,  so 
that- the  height  of  water  may  be  determined  by  looking  at 
this  gauge. 

Steam  gauge.  The  steam  gauge  is  a  device  for  recording 
the  pressure  of  the  steam  in  pounds.  It  is  so  arranged  that 
as  the  pressure  increases,  a  hand  on  a  dial  rotates,  much  like 
the  hands  on  a  clock;  and  the  pressure  is  read  from  the 
figure  to  which  the  hand  points. 

Safety  valve.  The  safety  valve  is  a  device  for  allowing 
the  steam  to  escape  when  a  certain  pressure  is  reached,  so 


Throttfe    Va/ve 


f-'ortvard  Rod 

Courtesy  of  Harper  &•  Brothers 
FIG.  92.  —  Parts  of  a  locomotive. 

as  to  prevent  the  possibility  of  an  explosion  occurring  in 
the  boiler.  This  valve  fits  into  a  hole  in  the  boiler ;  it  con- 
sists of  a  tight-fitting  plug,  which  is  kept  in  place  either 
by  a  spring  or  by  a  lever  with  a  weight  attached  to  it.  The 
tension  of  the  spring  or  the  weight  can  be  adjusted  to  allow 
the  steam  to  escape  at  any  desired  pressure. 

The  injector  is  a  device  which  fills  the  boiler  with  water ; 
this  is  operated  by  steam  pressure. 

Fuels.  Coal  is  the  fuel  generally  used.  The  draft  is 
increased  by  allowing  the  exhaust  steam  to  pass  into  the 
smoke  box;  and  as  this  is  under  considerable  pressure,  it 
rushes  out  of  the  box,  creating  a  partial  vacuum.  As  a  result, 


250 


SCIENCE  OF  HOME  AND   COMMUNITY 


air  is  drawn  in  through  the  pipes  and  fire  box,  thus  making  a 
draft.  Some  engines  are  so  built  that  they  use  liquid  oil 
instead  of  coal.  This  is  forced  in  the  form  of  a  fine  spray 
into  the  fire  box,  where  it  burns  quickly. 

Cylinder  and  valves.  The  parts  so  far  described  are  used 
to  convert  water  into  steam.  The  rest  of  the  engine  con- 
verts the  energy  into  the  motion  of  the  wheels.  The  steam 
is  led  from  the  boiler  into  the  steam  chest  S  (figure  93). 
From  here  two  openings  p  and  p' ',  called  ports,  lead  to  the 

cylinder  C.  Over  these 
openings  is  the  slide  valve 
V,  with  its  under  surface 
hollowed  out.  This  valve 
is  connected  with  an  eccen- 
tric. In  the  cylinder  is  a 
piston  connected  on  the  out- 
side by  means  of  a  connect- 
ing rod  with  the  drive  wheel 
of  the  locomotive. 

When  the  steam  enters 
the  chest  5,  it  passes 
through  p  or  p'  and  enters 
the  cylinder  C,  pushing  the 
piston  to  the  other  end  of  the  cylinder.  This  turns  the  wheel, 
which  moves  the  eccentric,  and  this  moves  the  valve  V  in 
such  a  way  that  the  port  p  is  closed  and  the  port  p'  is 
opened.  Thus  the  steam  enters  through  this  opening  and 
pushes  the  piston  back,  and  the  steam  in  the  other  end  of 
the  cylinder  is  forced  out  through  the  opening  p,  and  then 
through  the  exhaust  e  to  the  outside. 

Eccentric.  The  eccentric  consists  of  a  circular  plate 
mounted  on  the  crank  shaft.  The  opening  in  this  plate  is 
not  at  the  center,  but  at  one  side,  so  that  as  the  shaft  re- 
volves, it  gives  a  slight  motion  to  the  eccentric  rod,  similar 
to  that  given  by  a  small  crank,  and  this  rod  in  turn  moves 


FIG.  93.  —  Cylinder  and  steam  chest  of 
steam  engine. 


THE   LOCOMOTIVE 


the  slide  valve.  These  parts 
are  so  adjusted  that  the  slide 
valve  covers  and  uncovers  the 
openings  at  just  the  right  time 
to  allow  the  steam  to  enter 
each  in  turn.  Two  eccentrics 
are  provided  for  each  valve, 
one  for  the  forward  motion 
when  the  locomotive  is  going 
ahead,  and  another  for  the 
backward  motion  when  the 
locomotive  is  going  backward. 

The  link.  (See  figure  92.) 
One  very  important  part  of  the 
mechanism  is  the  link,  which 
consists  of  a  curved  piece  of 
steel,  the  ends  of  which  are 
connected  with  the  eccentric 
rods.  This  serves  two  im- 
portant uses,  it  enables  the 
engineer  both  to  reverse  the  en- 
gine and  to  control  the  amount 
of  steam  that  enters  the 
cylinder.  When  the  engineer 
wishes  to  reverse  the  engine, 
he  throws  over  a  lever  which 
is  connected  with  the  link, 
and  this  moves  the  slide 
valve  in  such  a  way  that  its 
position  is  quickly  changed, 
so  that  the  piston  is  made 
to  move  in  the  opposite  di- 
rection. 

Another  purpose  served  by 
the  link  is  to  enable  the  en- 


252  SCIENCE  OF  HOME  AND   COMMUNITY 

gineer  to  regulate  the  amount  of  steam  that  is  admitted 
to  the  cylinder.  When  the  train  is  starting,  a  large  amount 
of  power  is  needed,  and  so  steam  is  admitted  during  nearly 
the  whole  length  of  the  stroke  of  the  piston.  As  the  train 
gets  under  way,  the  steam  is  admitted  for  a  shorter  and 
shorter  portion  of  the  stroke,  until  when  under  full  head- 
way only  a  small  amount  of  steam  is  admitted.  When  the 
lever  is  set  in  the  center  no  steam  at  all  is  admitted  to  the 
cylinder ;  then  the  locomotive  goes  on  its  own  momentum. 

The  most  common  method  of  controlling  the  motion  of 
the  link  is  by  means  of  a  lever  in  the  cab,  which  is  worked 


^  FIG.  95.  —  Thirty  years  in  locomotive  building. 

by  hand  and  held  in  place  by  means  of  a  spring  clip  fitting 
into  notches.  In  some  locomotives  a  wheel  and  screw  gear 
is  used  in  place  of  the  lever.  In  still  other  cases  the  revers- 
ing gear  is  operated  by  means  of  compressed  air. 

Driving  wheels.  The  motion  of  the  piston  rod  is  com- 
municated to  the  locomotive  by  means  of  large  driving 
wheels,  varying  from  5  to  7  feet  in  diameter.  In  the  first 
locomotives  built,  a  single  pair  of  drivers  was  used;  but  in. 
later  types  two  and  even  three  driving  wheels  are  used  on 
each  side,  these  being  joined  by  means  of  a  shaft  so  that 
they  rotate  together.  This  gives  more  points  of  contact 


THE  LOCOMOTIVE  253 

with  the  rail,  and  so  there  is  less  slipping  when  the  train 
starts.  This  allows  better  time  to  be  made  when  there  are 
frequent  stopping  places. 

When  the  piston  rod  is  in  line  with  the  center  of  the  driv- 
ing wheel,  it  has  no  driving  force  and  is  said  to  be  at  dead 
center.  The  wheels  on  the  two  sides  of  the  locomotive  are 
so  arranged  that  when  those  on  one  side  are  at  dead  center, 
those  on  the  other  side  receive  the  maximum  driving  power 
of  the  piston.  Speeds  of  more  than  a  mile  a  minute  have 
been  maintained  for  a  period  of  eight  hours.  For  short 
distances,  rates  of  over  90  miles  an  hour  have  been  made. 

LABORATORY  EXERCISE  26 

Purpose.     To  study  the  parts  of  a  steam  engine. 

Apparatus.     Model  of  steam  engine  or  toy  engine. 

Directions.  Operate  the  model  and  notice  carefully  how 
each  part  works.  Make  a  drawing  and  label  the  parts.  By 
means  of  arrows  show  the  path  of  steam.  Explain  the  use  of 
each  part. 

FIELD  EXERCISE  5 

Purpose.     To  see  how  the  locomotive  works. 

Directions.  I .  If  there  are  locomotive  shops  in  town,  arrange 
with  the  superintendents  to  visit  them  with  the  class.  Or  arrange 
with  some  engineer  or  fireman  to  explain  to  the  class  the  working 
of  the  locomotive  (during  the  stop  of  the  locomotive  at  the  sta- 
tion). Notice  also  the  operation  of  the  brakes.  Have  some 
of  the  station  men  explain  the  operation  of  the  block  signals. 

2.  It  may  be  possible  also  to  visit  a  stationary  steam  engine 
in  some  power  house  in  town. 

Brakes.  Modern  trains  are  supplied  with  powerful  brakes, 
which  make  it  possible  to  stop  the  train  quickly.  One  of 
the  most  common  types  is  the  Westinghouse  brake,  which 
is  worked  by  compressed  air.  On  the  engine  is  a  tank  kept 
filled  with  compressed  air  under  high  pressure.  Under  each 
car  is  a  smaller  tank  connected  by  a  pipe  with  the  main  tank 


254  SCIENCE  OF  HOME  AND   COMMUNITY 

in  the.  engine.  On  each  car  connected  with  the  tank  is  a 
cylinder  provided  with  a  piston  which  connects  with  a  brake. 
The  engineer  is  able  to  control  the  working  of  all  the  brakes, 
and  by  turning  a  cock  the  compressed  air  is  caused  to  enter 
each  cylinder,  pushing  out  the  piston  which  sets  the  brakes. 

Railway  signals.  In  order  to  lessen  the  possibility  of 
accidents  various  systems  of  signals  are  used  so  that  the 
engineer  may  know  whether  any  other  trains  are  near  his. 
The  railroad  tracks  are  divided  into  blocks,  or  sections,  of  a 
few  miles  in  length.  At  the  beginning  of  each  block  are 
signals,  used  to  indicate  whether  any  train  is  in  that  block. 
No  train  is  supposed  to  enter  a  block  till  the  previous  train 
has  left  it.  Levers  are  attached  to  posts  by  the  side  of  the 
track,  and  by  their  position  they  indicate  whether  a  train 
is  in  the  block.  These  levers  may  be  operated  by  signal 
men,  or  automatically  by  electricity.  The  weight  of  the 
train  on  the  rails  closes  a  circuit,  which  operates  the  signal. 
On  a  double-track  road,  the  engineer  is  concerned  only  with 
those  trains  which  are  going  in  his  direction,  but  on  the 
single-track  road,  he  is  also  concerned  with  those  coming 
from  the  opposite  direction. 

Train  dispatcher.  The  trains  are  controlled  by  a  train 
dispatcher,  who  is  connected  by  telegraph  with  every  rail- 
road station.  He  keeps  a  careful  record  of  the  position  of 
every  train.  The  telegrapher  at  each  station  informs  the 
dispatcher  when  each  train  leaves  his  station.  Ordinarily 
the  trains  run  on  a  scheduled  time,  and  each  engineer  and 
conductor  knows  where  he  is  expected  to  be  at  any  given 
time  and  what  right  of  the  road  he  has.  But  when  a  train 
becomes  delayed,  the  schedule  is  interfered  with,  and  the 
trains  are  then  run  by  special  word  from  the  dispatcher, 
who  sees  that  proper  places  are  assigned  for  meeting  other 
trains,  with  as  little  danger  and  loss  of  time  as  possible. 
These  orders  for  the  trainmen  are  telegraphed  to  the  teleg- 
raphers at  the  stations  and  given  by  them  to  the  conductor. 


LOOMOTIVE  255 

Uses  of  the  steam  engine.  We  have  referred  to  one 
common  application  of  the  steam  engine,  that  is,  in  the  loco- 
motive. But  we  are  also  indebted  to  the  steam  engine  for 
many  other  services.  The  great  dynamo  which  generates 
electricity  for  lighting  our  homes  and  streets  and  for  running 
the  electric  cars  is  usually  turned  by  a  steam  engine. 

.  Other  applications  of  the  steam  engine  are  seen  in  factories, 
where  it  is  used  to  run  the  machinery.  The  great  majority 
of  the  common  things  that  enter  into  our  everyday  life  are 
factory  made.  Our  clothing  is  made  from  thread  woven 
or  knit  in  mills.  Many  of  our  foods  have  passed  through 
some  process  in  a  factory.  The  shingles  and  boards  in  the 
houses  that  furnish  us  shelter  have  been  prepared  in  mills 
run  by  steam  engines.  The  furnaces  and  stoves  that  warm 
our  homes  have  come  from  the  factory.  The  furniture  in 
our  homes,  the  rugs  on  the  floor,  and  the  curtains  at  the 
window  have,  somewhere  in  their  process  of  manufacture, 
been  fashioned  by  machinery  run  by  a  steam  engine.  The 
books  and  magazines  that  we  read  and  the  paper  that  comes 
to  our  doors  daily  have  been  printed  on  presses  operated  by 
the  steam  engine. 

In  some  cases  water  falls  and  electricity  furnish  the  power 
to  run  the  machines  of  the  factory ;  but  in  most  cases,  the 
electricity  is  generated  by  steam  power,  and  the  steam 
engine  is  by  far  the  most  common  source  of  power  used 
in  factories. 

SUPPLEMENTARY  QUESTIONS  FOR   CLASS  DISCUSSION 

1.  What  do  you  consider  the  most  important  use  of  the 
locomotive  ? 

2.  Compare  the  methods  of  traveling  from  Boston  to  Wash- 
ington used  100  years  ago  with  the  methods  used  now. 

3.  What  was  Watt's  contribution  to  the  steam  engine? 

4.  What  are  the  methods  used  for  generating  steam  in  a 
locomotive  ? 


256  SCIENCE  OF  HOME  AND   COMMUNITY 

5.  How  is  the  energy  of  the  steam  converted  into  the  motion 
of  the  wheels  ? 

6.  What  are  the  uses  of  the  link  ? 

7.  What  .precautions  are  taken  to  prevent  accidents  on  rail- 
roads ? 

REFERENCES 

Cressey,   Discoveries  and   Inventions  of  the    Twentieth   Century, 

E.  P.  Button,  New  York  City.     Chap.  12. 
Doubleday,   Stories   of  Inventors,   Doubleday    Page   Co.,    New 

York  City.     Pages  51-67. 
Harpers'  Machinery  Book  for  Boys,  Harper  Bros.,  New  York 

City.     Chap.  7. 
Howden,  Boys9  Book  of  Locomotives,  McClure  Co.,  New  York 

City. 
Williams,  How  It  Works,  T.  Nelson  and  Sons,  New  York  City. 

Chaps,  i  and  2. 


CHAPTER  XVII 
THE   ELECTRIC  TROLLEY 

What    part  does   electricity   play   in   the  run- 
ning of  the  trolley? 

Uses  of  electric  cars.  One  of  the  most  recent  develop- 
ments in  modern  means  of  travel  is  the  electric  trolley  and 
it  has  grown  rapidly  in  popularity.  Almost  every  city  now 
has  its  system  of  electric  cars,  and  in  the  more  thickly  settled 
portions  of  the  country,  a  network  of  these  lines  connects 
the  larger  cities.  The  trolley  is  taking  the  place,  to  some 
extent,  of  the  steam  cars.  It  has  one  great  advantage  over 
the  steam  cars  in  that  no  special  roadbed  need  be  con- 
structed, as  the  rails  can  be  laid  up  hill  and  down,  on  roads 
already  constructed  or  across  country.  This  makes  the  cost 
of  construction  very  much  less.  In  some  localities  trolleys 
are  being  constructed  through  regions  of  beautiful  scenery, 
and  the  trolley  is  a  source  of  much  pleasure  during  the  sum- 
mer months,  as  well  as  an  important  business  necessity  at 
all  times  of  the  year.  Like  the  railroad  the  electric  car 
widens  the  residential  area  about  a  big  city  and  enables 
business  people  to  find  pleasant  homes  in  the  suburbs. 

History  of  electric  cars.  Crude  forms  of  electric  cars, 
were  made  many  years  before  they  became  a  practical 
success.  In  1835  Thomas  Davenport  of  Vermont  con- 
structed a  small  circular  railway  at  Springfield,  Mass.,  on 
which  he  operated  a  car  driven  by  a  motor.  This  was 
probably  the  first  electric  car  ever  built.  Following  this, 
other  inventors  at  various  times  made  different  forms  of 
s  257 


258  SCIENCE  OF  HOME  AND   COMMUNITY 

electric  cars ;  but  the  first  practical  electric  locomotive  was 
made  by  Doctor  Siemens.  This  was  exhibited  at  the  In- 
dustrial Exposition  in  Berlin  in  1879.  It  attracted  a  great 
deal  of  attention,  and  inventors  from  various  parts  of  the 
world  began  to  devote  more  time  to  perfecting  an  electric 
car ;  so  that  from  this  may  be  said  to  date  the  development 


Courtesy  of  Harper  6*  Brothers 
FIG.  96.  —  The  first  electric  railway. 

of  the  modern  electric  car.  Improvements  in  the  dynamo 
and  motor  have  made  the  perfection  of  the  practical  trolley 
car  possible. 

First  electric  car.  Shortly  after  this  Exposition,  the  first 
commercial  electric  railway  in  the  world  was  constructed  in 
Germany  between  Berlin  and  Lichterfelde,  a  distance  of 
about  a  mile  and  a  half.  For  this  purpose  an  old  horse  car 
was  used  and  converted  into  an  electric  car  by  mounting  a 
motor  between  the  axles. 

Electric  cars  in  America.  In  this  country  special  atten- 
tion was  given  to  electric  cars  by  Stephen  Field  and  Thomas 
Edison.  In  1881  each  constructed  a  short  electric  railway, 


THE  ELECTRIC  TROLLEY  259 

Field  in  Stockbridge,  Mass.,  and  Edison  in  Menlo  Park, 
N.  J.  In  1883  an  electric  railway  was  constructed  at  the 
Chicago  Railway  Exposition.  The  electricity  was  conveyed 
to  the  motor  by  means  of  a  central  rail.  The  first  com- 
mercial electric  street  railway  in  this  country  was  constructed 
in  1885  between  Baltimore  and  Hampden,  Md.,  a  distance 
of  two  miles.  Since  that  time  many  improvements  have 
been  made  in  the  electric  car,  and  it  has  advanced  with 
rapid  strides,  until  now  the  trolley  is  a  common  sight  in  all 
parts  of  the  United  States.  A  few  figures  will  give  some 
idea  of  this  wonderful  growth.  In  1885  there  was  one  electric 
railway  in  the  United  States;  in  1890  there  were  144;  in 
1915  there  were  1027  electric  railway  companies,  46,500 
miles  of  track,  and  79,000  passenger  cars. 

The  mechanism  of  the  trolley  car.  We  may  now  attempt 
to  understand  some  of  the  principles  that  underlie  the  work- 
ing of  the  trolley  car.  If  we  take  into  account  all  the  de- 
tails, it  is  a  very  complicated  piece  of  mechanism,  but  some 
of  the  simpler  facts  regarding  it  can  be  easily  understood. 
As  electricity  is  needed  to  run  the  trolley  car,  let  us  first 
notice  how  this  electricity  is  made.  This  takes  us  first  to 
the  power  house. 

Dynamo.  The  dynamo  is  the  machine  by  means  of  which 
electricity  is  generated.  It  consists  of  two  essential  parts, 
an  armature  and  a  pair  of  field  magnets.  The  armature 
consists  of  a  coil,  or  series  of  coils,  of  wire  and  is  placed  be- 
tween two  field  magnets.  The  armature  is  so  mounted  on 
an  axle  that  it  rotates  between  the  magnets.  Magnets 
have  power  to  attract  iron,  and  if  iron  filings  are  scattered 
over  a  bar  magnet  they  will  arrange  themselves  in  regular 
lines.  When  the  armature  revolves  between  the  magnets, 
it  is  cutting  across  the  lines  of  force  running  out  from  these 
magnets,  and  as  a  result  an  electric  current  is  set  up  along 
the  wire.  By  means  of  proper  connections  this  current  may 
be  led  out  and  carried  away  by  wires.  Two  kinds  of  current 


260  SCIENCE  OF  HOME  AND   COMMUNITY 

may  be  produced  by  these  dynamos,  the  alternating  current 
and  the  direct  current.  In  alternating  currents  the  direction 
in  which  the  electricity  is  passing  changes  with  each  half 
revolution  of  the  coil  of  wire.  In  direct  currents  the  current 
is  passing  in  the  outside  circuit  in  the  same  direction  all  the 
time. 

In  order  to  produce  strong  currents,  very  powerful  electro- 
magnets are  used  with  many  coils  of  wire  in  the  armature. 
It  does  not  matter  whether  the  magnets  are  stationary  and 
the  armature  revolves,  or  whether  the  armature  is  stationary 
and  the  magnets  revolve.  Dynamos  of  both  forms  are  used. 

DEMONSTRATION  19 

Purpose.     To  illustrate  the  principle  of  the  dynamo. 

Apparatus.  Galvanometer,  bar  magnet,  primary  and  second- 
ary coil  (the  inner  one  removable),  wire. 

Directions.  Connect  a  coil  of  wire  with  a  galvanometer. 
Thrust  a  bar  magnet  into  the  center  of  the  coil  and  watch  the 
needle.  After  the  bar  comes  to  rest,  is  there  any  current? 
Remove  the  magnet  and  notice  the  needle.  Connect  a  primary 
coil  of  wire  with  a  cell.  Thrust  this  coil  into  the  center  of  the 
secondary  coil  used  in  the  previous  experiment.  Watch  the 
needle.  Remove  the  coil.  Under  what  conditions  is  a  current 
generated  in  the  secondary  coil  of  wire  ? 

Power  to  turn  dynamos.  Some  power  must  be  used  to 
turn  the  dynamos.  For  this  purpose,  water  wheels,  steam 
engines,  and  gas  engines  are  used.  Water  is  the  cheapest 
of  these  and  is  very  widely  used.  The  power  plants  at 
Niagara  Falls  are  the  best-known  examples  of  the  use  of 
water  power.  The  electricity  here  generated  may  be  carried 
many  miles  to  points  where  it  is  used.  The  electric  current 
is  taken  from  Niagara  a  distance  of  154*  miles  to  the  city  of 
Syracuse,  where  it  is  used  to  drive  the  street  cars.  In  other 
localities  it  is  being  carried  even  longer  distances  than  this. 
At  the  present  time  the  most  common  means  used  for  turn- 


THE  ELECTRIC  TROLLEY  261 

ing  the  dynamo  is  the  steam  engine.  In  some  places  the  gas 
engine  is  used. 

How  the  current  is  conducted  to  the  car.  From  the  power 
house  the  electricity  is  conducted  by  means  of  wires  to  the 
trolley  cars.  In  the  system  most  commonly  used,  the 
electricity  is  conveyed  by  a  wire  suspended  over  the  tracks. 
The  electricity  passes  from  this  to  the  car  through  the  trolley 
pole.  Powerful  springs  at  the  base  of  the  pole  push  the  pole 
and  the  little  wheel  at  its  end  upward  and  in  constant  con- 
tact with  the  wire.  From  the  trolley  base  the  current  is 
conducted  to  the  various  parts  of  the  car,  and  returns  by 
means  of  the  rails  on  which  the  car  runs.  In  order  to  com- 
plete the  circuit,  the  ends  of  the  rails  are  either  connected 
by  wires  or  else  welded.  In  order  to  supply  enough  elec- 
tricity to  all  parts  of  the  system,  different  wires,  known  as 
feeders,  are  run  from  the  main  supply  of  the  current,  and 
connect  with  various  parts  of  the  system. 

Controller.  As  we  watch  the  motorman  running  the  car, 
we  notice  that  he  controls  the  car  by  means  of  three  handles, 
one  for  the  brakes,  and  two  on  a  boxlike  structure  called 
the  controller.  When  he  wishes  to  start  the  car,  one  of  the 
handles  is  turned  a  notch  at  a  time  till  a  place  is  reached 
where  it  is  allowed  to  remain  stationary.  When  he  wishes  to 
stop,  the  handle  is  turned  back  again  and  the  brakes  applied. 
If  he  wishes  to  make  the  car  go  backwards,  he  moves  another 
handle  and  then  turns  the  first  handle  as  before. 

This  controller  serves  three  purposes :  first,  it  connects 
the  motor  with  the  circuit,  so  that  the  car  can  be  started  or 
stopped;  second,  it  regulates  the  amount  of  electricity 
which  passes  to  the  motor,  so  that  the  speed  of  the  car  can 
be  controlled;  and  third,  it  governs  the  direction  in  which 
the  car  goes,  so  that  it  can  be  made  to  go  either  forward  or 
backward. 

If  the  full  current  were  turned  into  the  motor  suddenly, 
it  would  cause  the  car  to  start  with  an  unpleasant  jerk  and 


262  SCIENCE  OF  HOME  AND  COMMUNITY 

it  might  injure  the  motor.  In  order  to  avoid  this,  resistance 
coils  are  connected  with  the  motor,  so  that  when  the  handle 
is  turned  to  the  first  notch,  the  current  passes  through  both 
the  coils  and  the  motor,  and  thus  the  motor  at  first  receives 
only  a  portion  of  the  full  strength  of  the  current.  As  the 
handle  is  turned  still  further  around,  these  resistance  coils 
are  cut  out,  till  finally  the  motor  receives  the  full  strength 
of  current  and  runs  at  full  speed. 

Circuit  breakers.  In  order  to  protect  the  parts  of  the 
machinery  on  the  car  from  being  injured  by  too  strong  a 
current,  circuit  breakers  and  fuses  are  provided.  These 
circuit  breakers  are  so  arranged  that  when  too  strong  a 
current  passes  through  them  they  automatically  open  the 
circuit.  Sometimes  when  riding  on  the  trolleys,  one  hears 
a  noise  like  an  explosion  which  is  due  to  the  working  of  this 
circuit  breaker.  If  you  watch  the  motorman,  you  will  see 
that  he  reaches  up  and  turns  back  a  handle  connected  with 
the  circuit  breaker,  thus  making  a  connection  again. 

Fuse.  A  fuse  serves  the  same  purpose.  This  is  com- 
posed of  certain  metals  which  melt  when  a  strong  current 
passes  through  them,  thus  opening  the  circuit  and  preventing 
the  current  from  passing  through  the  remaining  portions 
of  the  machinery. 

Motor.  The  machine  which  actually  makes  the  wheels 
of  the  car  turn  is  the  motor,  which  is  placed  under  the  car 
on  the  axles.  The  motor  is  constructed  the  same  as  a 
dynamo ;  that  is,  it  is  a  reversible  machine.  If  it  is  turned 
by  some  outside  power,  it  generates  electricity ;  if  electricity 
is  conducted  through  it,  the  parts  begin  to  revolve.  So  the 
same  machine  can  be  used  for  either  a  dynamo  or  motor. 
As  a  matter  of  efficiency,  however,  it  is  found  better  to  make 
machines  intended  for  motors  somewhat  different  from  those 
intended  for  dynamos. 

The  motor  has  the  same  essential  parts  as  the  dynamo, 
that  is,  an  armature  and  two  magnets.  When  two  magnets 


THE   ELECTRIC   TROLLEY 


263 


are  brought  together,  if  the  north  end  of  one  is  brought  near 
the  south  end  of  the  other,  they  will  be  drawn  towards  each 
other.  (See  figure  97.)  If  the  two  north  ends  or  the  two 
south  ends  are  brought  together,  they  will  be  pushed  apart. 
This  can  be  well  illustrated  by  means  of  a  bar  magnet 
and  a  compass,  which  is  a  magnet  mounted  so  that  it  can 
rotate.  If  the  south  end  of  the  magnet  is  brought  near 
the  north  end  of  the  needle,  the  needle  will  turn  around 
till  its  north  end  points  towards  the  south  end  of  the 
magnet.  If  the  magnet  be  constantly  moved, 
the  needle  may  be  kept  in  constant  motion. 
When  an  electric  current  is  passed  through 
a  motor,  the  field  magnets  and  armature 
both  become  magnets  and  on  account  of  the 
attraction  of  unlike  poles  and  the  repulsion 
of  like  poles,  the  armature  is  caused  to  re- 
volve. This  is  so  constructed  as  to  make 
the  motion  continuous  as  long  as  the  current 
passes  through  the  motor.  The  motor  is 
connected  with  the  axles  of  the  car  by  means  of  gears,  and 
thus  the  wheels  are  made  to  rotate  and  the  car  to  move. 

Thus  the  long  story  that  began  with  the  burning  of  coal 
in  the  fire  box  of  an  engine  at  the  power  house,  is  now  com- 
pleted when  the  energy  thus  generated  is  made  to  move 
wheels  of  a  trolley  miles  away. 


FIG.  97. — Illustrat- 
ing principle  of 
electric  motor. 


LABORATORY  EXERCISE  27 

Purpose.     To  see  how  the  motor  works. 

Apparatus.  Two  bar  magnets,  wire,  two  long  nails,  small 
motor,  two  cells. 

Directions,  i.  In  order  to  understand  the  principles  in- 
volved in  the  motor,  we  will  first  study  the  action  of  two  bar 
magnets  towards  each  other.  Make  a  stirrup  of  a  piece  of  wire 
and  suspend  a  bar  magnet  in  this  by  means  of  a  string.  Bring 
the  north  pole  of  the  other  magnet  near  the  north  pole  of  the 


264  SCIENCE  OF  HOME  AND   COMMUNITY 

suspended  magnet.  Bring  it  near  the  south  end.  What  dif- 
ference in  action  do  you  note?  Bring  the  south  end  of  the 
magnet  near  the  south  end  and  then  near  the  north  end  of  the 
suspended  magnet.  What  is  the  law  governing  the  action  of 
magnets  towards  each  other  ? 

2.  Make  two  electromagnets  by  winding  six  or  seven  feet 
of  insulated  wire  around  a  long  nail.     Connect  each  electro- 
magnet with  a  cell.     Suspend  one  the  same  as  was  done  with 
the  magnet  in  the  previous  experiment.     Bring  the  ends  of  the 
other  electromagnet  in  turn  near  the  ends  of   the   suspended 
magnet.     What  happens? 

3.  Connect  a  small  motor  with  a  cell  and  notice  how  the 
parts  work.     How  does  the  previous  experiment  help  you  to 
understand  what  takes  place  ? 

Brakes.  Some  of  the  smaller  cars  are  stopped  by  means 
of  hand  brakes,  but  most  of  the  larger  cars  are  fitted  with 
brakes  operated  by  compressed  air  and  similar  to  those 
used  on  railway  trains.  The  air  is  compressed  by  means  of 
a  motor  which  works  automatically,  always  keeping  the 
pressure  up  to  a  certain  point.  We  often  hear  this  machine 
whirring  while  we  are  riding  on  the  trolley;  it  suddenly 
stops  when  a  certain  air  pressure  has  been  reached,  and  then 
starts  again  when  the  motorman  has  used  the  brakes  and 
the  pressure  has  been  lessened. 

Lighting  and  heating.  The  cars  are  lighted  and  usually 
heated  by  current  taken  from  the  trolley  wire.  The  electric 
heaters  are  usually  placed  at  intervals  on  both  sides  of  the 
car. 

In  many  cars  there  is  a  system  of  electric  buttons,  con- 
nected with  a  bell  near  the  motorman  for  signaling.  When 
a  person  wishes  the  car  to  stop,  he  pushes  a  button  and  this 
causes  the  bell  to  ring  as  a  signal  to  the  motorman. 

Electric  locomotive.  There  are  conditions  in  which  the 
smoke  of  the  ordinary  locomotive  is  very  offensive  and  in 
fact  unsafe.  To  insure  safety  in  tunnels  and  to  avoid  the 


THE  ELECTRIC  TROLLEY  265 

danger  of  smoke  and  sparks  elsewhere  the  electric  locomotive 
is  now  taking  the  place  of  the  steam  locomotive.  In  1915 
there  were  2250  miles  of  steam  railway  tracks  in  the  United 
States  that  had  been  changed  to  electric  operation,  and  some 
railroads  are  extending  its  use  to  great  sections  of  their  lines. 
The  electric  locomotive  can  also  be  made  of  much  smaller 
weight  than  the  steam  locomotive.  But  it  has  to  be  heavy 
enough  so  the  drivers  will  not  slip  if  equally  heavy  trains 
are  hauled.  It  is  run  by  motors  similar  to  the  ordinary 
trolley  car,  but  more  powerful,  and  a  single  engine  may  draw 
a  whole  train  of  passenger  or  freight  cars. 

SUPPLEMENTARY  QUESTIONS  FOR  CLASS  DISCUSSION 

1 .  What  advantages  has  the  trolley  over  the  locomotive  ? 

2.  What  parts  do  the  dynamo  and  the  motor  play  in  running 
the  trolley? 

3.  In  what  ways  are  the  dynamo  and  motor  alike? 

4.  How  does  the  motorman  control  his  car? 

5.  What  provision  is  made  on  the  electric  cars  for  protection 
from  accidents? 

6.  How  is  the  electricity  produced  that  runs  the  cars  ? 

7.  How  does  the  motor  change  electricity  into  action? 

REFERENCES 

Cressey,  Discoveries  and  Inventions  of  the  Twentieth  Century, 
E.  P.  Button  Co.,  New  York  City.  Chap.  13. 

Harper's  Electricity  Book  for  Boys,  Harper  Bros.,  New  York 
City.  Chap.  10. 


CHAPTER  XVIII 
THE  AUTOMOBILE 

What  should  a  person  know  about  an  automobile 
in  order  to  run  one  successfully  ? 

Uses  of  automobiles.  Automobiles  now  seem  to  be  used 
for  almost  every  purpose  that  any  type  of  vehicle  has  ever 
served.  They  began  as  pleasure  cars.  Now  they  are  put 
to  a  great  variety  of  commercial  uses :  delivery  wagons , 
motor  trucks,  plows,  and  jitney  busses.  In  the  great  Euro- 
pean War  they  were  used  to  propel  gun  carriages  and  to 
transport  soldiers  and  supplies.  The  battle  of  the  Marne 
was  won  by  the  French  and  Verdun  was  saved  through  the 
use  of  automobiles.  Moreover,  the  service  of  the  auto- 
mobile seems  to  be  only  in  its  beginning.  It  doubtless  has 
an  even  greater  future  before  it,  when  it  will  take  the  place 
to  some  extent  of  locomotives  and  street  electric  railways. 
For  lines  of  business  that  require  a  person  to  travel  short 
distances  the  automobile  is  a  great  time  saver,  enabling  him 
to  do  a  larger  amount  of  work  in  a  day.  t 

History  of  the  automobile.  The  first  carriage  to  be  pro- 
pelled by  an  engine  was  built  in  1769,  by  a  Frenchman 
named  Cugnot.  This  carriage  was  propelled  by  a  steam 
engine  placed  on  the  frame  of  the  carriage.  It  was  a  very 
clumsy  affair  mounted  on  three  wheels.  It  traveled  only 
three  or  four  miles  an  hour,  it  had  to  stop  every  ten  minutes 
to  get  up  steam,  and  it  could  carry  only  three  persons. 
Compare  this  with  our  modern  automobile ! 

266 


THE  AUTOMOBILE 


267 


268  SCIENCE  OF  HOME  AND   COMMUNITY 

The  next  steam  carriage  was  made  in  England  in  1801 
by  Richard  Trevithick.  The  use  of  these  carriages  so 
frightened  the  horses  that  a  law  was  passed  requiring  a 
man  to  walk  ahead  of  the  steam  carriage  with  a  red  flag 
to  give  warning  of  its  approach.  Later  they  were  prohibited 
from  using  the  highways  altogether,  because  they  inter- 
fered with  the  horse  traffic.  It  was  not  until  1896  that  the 
"  Red  Flag  Act  "  was  repealed. 

During  the  year  1895  in  the  city  of  Chicago,  when  one 
of  the  first  automobiles  was  passing  along  Michigan  Avenue, 
the  driver  was  stopped  by  a  policeman  and  told  that  horse- 
less carriages  were  not  permitted  on  the  streets. 

No  great  progress  was  made  in  the  development  of  power- 
propelled  vehicles  till  after  1885,  when  Gottlieb  Daimler 
invented  the  high-speed  gasoline  engine.  But  it  was  not 
until  the  beginning  of  the  present  century  that  the  auto- 
mobile began  to  make  rapid  development.  No  machinery 
or  invention  for  travel  has  ever  made  such  rapid  strides  as 
has  the  automobile  during  the  past  fifteen  years.  In  1895 
the  first  automobile  race  was  held  in  this  country.  The 
winning  car  was  driven  by  a  four  horse-power  engine.  It 
traveled  at  the  rate  of  7-^  miles  an  hour.  About  twenty 
years  later  racing  cars  had  reached  a  speed  of  120  miles  per 
hour. 

In  1898  there  were  probably  not  100  automobiles  in  the 
entire  United  States ;  by  the  end  of  1918  there  were  approx- 
imately 6,000,000  cars  and  trucks  registered  in  the  United 
States,  or  one  for  every  18  persons,  that  is,  about  one  for 
every  4  families.  This  is  an  increase  of  20  per  cent  over  the 
number  registered  in  1917,  and  nearly  six  times  as  many  as 
there  were  seven  years  previous  in  1 9 1 1 .  In  the  states  of  Iowa 
and  Nebraska  there  is  one  automobile  for  every  seven  per- 
sons. The  entire  population  of  these  states  can  be  carried 
in  their  cars.  One  third  of  the  total  number  in  the  country 
is  registered  in  the  five  states  of  New  York,  Ohio,  California, 


THE  AUTOMOBILE 


269 


270  SCIENCE  OF  HOME  AND   COMMUNITY 

Pennsylvania,  and  Illinois.  There  are  ten  states  in  which  the 
number  registered  in  each  is  over  200,000.  Besides  the  five 
mentioned  above  these  include  Indiana,  Iowa,  Michigan, 
Minnesota,  and  Texas. 

In  1904  there  were  made  in  this  country  11,000  cars; 
in  1909,  125,000;  in  1915,  almost  900,000;  and  in  1917, 
nearly  2,000,000. 

Types  of  automobiles.  Automobiles  may  be  divided  into 
two  types,  according  to  the  power  used  to  run  the  machine, 
—  the  electric  car  and  the  gasoline  car.  Steam  also  has 
been  used,  but  its  disadvantages  were  so  many  that  it  has 
been  largely  abandoned. 

Comparison  of  gasoline  and  electric  cars.  Each  type  of 
car  has  its  advantages  and  disadvantages.  The  advantages 
of  the  electric  car  are  that  it  is  more  simple  in  construction 
and  more  easily  managed,  and  it  is  without  odor,  vibrations, 
or  noise. 

The  advantages  of  the  gasoline  car  are  that  it  is  lighter 
and  cheaper;  it  can  travel  over  a  larger  range  of  country, 
as  gasoline  can  now  be  obtained  in  almost  every  village,  and 
the  supply  of  gasoline  can  be  pumped  into  the  tank  in  a  few 
minutes.  When  everything  is  considered,  the  gasoline  car 
has  more  advantages  than  the  electric  car  and  so  is  much 
more  widely  used. 

Parts  of  an  automobile.  The  gasoline  automobile  is  a 
very  complicated  piece  of  mechanism.  For  the  sake  of 
simplicity,  we  may  say  that  it  is  composed  of  the  following 
parts :  i.  the  axles  and  wheels ;  2.  the  supporting  frame  and 
springs;  3.  the  body  or  part  that  carries  the  load;  4.  the 
power  plant;  5.  the  clutch  and  gear  box;  6.  the  power 
transmission  system;  7.  the  lighting  system;  and  8.  the 
mechanism  by  which  the  driver  controls  the  car.  (See 
figures  98,  99.) 

Axles  and  wheels.  The  front  axle  is  attached  solidly  to 
the  frame  and  is  not  pivoted  at  the  center,  like  the  axle  of  a 


THE  AUTOMOBILE 


271 


carriage.  At  the  end  of  this  axle  the  wheel  is  mounted  on 
a  short  axle  pivoted  in  such  a  way  that  it  can  be  moved,  so 
as  to  turn  the  vehicle  in  any  desired  direction.  The  spindles 
carrying  the  wheels  are  connected  by  a  tie  bar,  so  that  both 
front  wheels  move  together.  The  motion  of  these  wheels  is 
controlled  by  a  steering  wheel,  whose  motion  turns  a  lever 
connected  with  the  spindle  on  which  the  wheel  revolves. 
(See  figure  100.)  The  rear  axle  not  only  helps  support  the 
weight  of  the  car,  but  it  is  here  that  the  power  of  the  engine 


Wheel  Spi 


Tie  Bar 

Steering  Arm- 

FIG.  100.  —  Front  axle  and  steering  mechanism. 


(See 


is  transmitted  to  the  axle  so  as  to  move  the  car. 
figure  101.) 

Wheels  and  tires.  The  spokes  of  the  wheel  are  made  either 
of  wood  or  wire.  On  large  motor  vehicles  used  for  carrying 
heavy  loads,  solid  rubber  tires  are  frequently  used ;  but  for 
the  ordinary  car,  pneumatic  tires  are  used.  These  consist 
of  a  tough  outer  casing  which  comes  in  contact  with  the 
road,  and  inside  of  this  and  protected  by  it  from  wear  is  a 
tube  of  rubber  which  is  air  tight.  This  is  filled  with  air 
under  pressure  by  means  of  an  air  pump.  In  order  to  pre- 


272 


SCIENCE   OF  HOME  AND    COMMUNITY 


vent  skidding,  the  outer  casing  is  made  with  a  roughened 
surface,  and  in  wet  weather  chains  are  attached  to  the  tires. 
To  reduce  friction,  the  wheels  are  mounted  on  the  axles  by 
means  of  antifriction  ball  or  roller  bearings. 

Frame  and  springs.  The  frame  supports  most  of  the 
weight  of  the  car,  connects  the  axles,  and  carries  the  springs. 
The  frame  is  usually  made  of  steel ;  and  the  lightness  and 
strength  of  the  modern  automobile  are  due  largely  to  the 
new  varieties  of  steel  that  have  been  introduced  in  recent 


\DriveAxte 
" 'Bearing  Mousing 
owBearing 

FIG.  101.  —  Semi-floating  automobile  rear  axle  construction  with  shafts  and  gear- 
ing mounted  on  double  row  ball  bearings. 

years.     The  frame  is  supported  on  the  axles  by  means  of 
springs. 

Body.  A  number  of  types  of  bodies  are  made,  according 
to  their  use.  The  following  are  among  the  most  common : 
the  roadster,  coupe*,  touring,  limousine,  and  truck.  These 
may  be  made  of  either  wood  or  metal.  In  order  to  reduce 
the  air  resistance,  which  is  especially  noticeable  at  high 
speeds,  some  bodies  are  made  in  a  torpedo  shape  with 
gradual  curves  and  unbroken  sides.  These  bodies  are  of 
either  the  closed,  open,  or  semi-closed  type.  Nearly  all 
types  have  a  transparent  wind  shield  to  protect  the  operator 
from  dust  and  cold  wind.  Either  celluloid  or  glass  is  used 
for  this  shield. 


THE  AUTOMOBILE 


273 


Power  plant.  The  power  plant  consists  of  the  following 
parts :  a  gas  engine,  a  carburetion  system,  an  ignition  sys- 
tem, a  lubrication  system,  and  a  cooling  system. 

How  the  gas  engine  works.  The  gas  engine  is  known  as 
an  internal  combustion  machine,  because  the  fuel  is  burned 
inside  the  cylinder  and  the  explosion  thus  formed  forces 
back  the  piston.  Before  entering  the  cylinder,  the  gasoline 
is  changed  to  a  gas  and  mixed  with  air  in  the  carburetor. 
The  mixture  is  set  on  fire  by  means  of  an  electric  spark. 


(Tyftne/t 


Carburetor 


FIG.  1 02.  —  Simple  two-cylinder  opposed  water-cooled  motor. 

The  common  gas  engine  is  spoken  of  as  a  four-cycle 
engine,  as  there  are  four  distinct  steps  in  the  action  of  the 
piston.  The  first  stroke  of  the  piston  sucks  in  the  mixture 
of  air  and  gas  from  the  carburetor  into  the  cylinder.  The 
second  stroke  compresses  this  mixture.  At  the  beginning 
of  the  third  stroke,  the  explosion  of  the  gases  takes  place 
and  the  piston  is  forced  back.  On  the  fourth  stroke  the 
burned  gases  are  forced  out  of  the  cylinder  through  a  valve. 
These  strokes  are  called  respectively  suction,  compression, 
combustion,  and  exhaustion.  (See  figures  103-106.) 

Only  once  in  four  strokes,  therefore,  is  the  motive  power 


274 


SCIENCE  OF  HOME  AND   COMMUNITY 


FIG.  103.  —  First  stroke  (suction).  —  Gas  and  air  admitted  to  cylinder. 


FIG.  104.  —  Second  stroke  (compression) .  —  Mixture  of  gas  and  air  compressed. 


FIG.  105.  —  Third  stroke  (combustion).  —  Mixture  is  exploded  and  expands, 
driving  the  piston  forward. 


Courtesy  of  Harper  &  Brothers 
FIG.   106.  —  Fourth  stroke  (exhaustion).  —  The  burned-out  mixture  of  gas  and 

air  expelled  from  the  cylinder. 
THE  FOUR-CYCLE  GAS  ENGINE. 


THE  AUTOMOBILE  275 

applied  to  the  piston.  In  order  to  keep  the  piston  running 
during  the  other  three  strokes,  a  heavy  flywheel  is  provided, 
whose  momentum  keeps  the  axle  rotating  until  the  next 
explosion. 

In  order  to  give  a  more  even  application  of  power,  auto- 
mobiles are  now  furnished  with  engines  of  four,  six,  eight,  or 
even  more  cylinders.  A  four-cylinder  engine  would  be  so 
arranged  that  the  driving  gear  would  receive  an  impetus 
four  times  as  frequently  as  it  would  from  an  engine  of  one 
cylinder. 

Starting.  In  order  to  start  the  engine,  some  power  must 
be  used  to  give  the  piston  a  few  strokes  till  an  explosion 
occurs.  In  some  cars  this  is  done  by  hand,  by  means  of  a 
crank  attached  to  the  front  of  the  car.  Other  cars  have 
electric  starters,  in  which  the  power  to  start  the  piston  is 
furnished  by  a  motor,  driven  by  electricity  from  a  storage 
battery.  This  is  controlled  by  pressing  a  button  or  lever. 

Comparison  with  steam  engine.  The  gas  engine  differs 
from  the  steam  engine  in  a  number  of  ways.  In  the  'first 
place  the  fuel  is  burned  inside  of  the  cylinder  instead  of  in 
a  fire  box.  In  the  four-cycle  engine  the  propelling  force  is 
applied  only  once  in  four  strokes,  and  on  only  one  side  of 
the  piston ;  while  in  the  steam  engine  it  is  applied  at  every 
stroke,  alternating  on  the  two  sides  of  the  piston.  A  steam 
engine  will  start  as  soon  as  the  steam  is  admitted  to  the 
cylinder;  while  in  order  to  start  a  gas  engine,  the  crank 
shaft  must  first  be  rotated  by  some  external  means.  A 
steam  engine  can  begin  to  do  work  at  once  as  soon  as  the 
steam  moves  the  piston  head,  while  a  gas  engine  must  be 
started  first  without  connection  with  the  axle  of  the  auto- 
mobile, and  then  the  load  is  gradually  applied  by  means  of  a 
clutch. 

Carburetion.  Before  the  gasoline  is  allowed  to  enter  the 
cylinder,  it  is  changed  to  a  gas  and  mixed  with  air,  so  that 
it  will  explode  in  the  cylinder.  The  machinery  which  does 


276 


SCIENCE  OF  HOME  AND   COMMUNITY 


this  is  called  the  carburetion  system.     The  most  common 
kind  of  carburetor  is  the  spraying  type.     The  gasoline  is 

forced  under  great  pressure 
through  small  openings, 
forming  a  spray  which 
quickly  changes  to  a  vapor. 
At  the  same  time,' it  is 
mixed  with  air  in  the  pro- 
portion of  about  one  part 
of  gasoline  vapor  to  six  or 
seven  parts  of  air.  This 
mixture  is  led  into  the 
cylinder  and  put  under 
pressure  before  it  is  ex- 
ploded. 

When  the  gases  escape  from  the  engine  after  the  explosion, 
they  emit  a  very  loud  noise.  Jn  order  to  silence  this,  a 
muffler  is  used.  This  is  cylindrical  in  shape  and  is  made  up 
of  several  compartments,  separated  by  partitions  in  which 
is  a  series  of  holes;  through  these  holes  the  gases  pass,  so 
that  they  finally  leave  the  muffler  with  only  a  slight  hissing 


Air  fritet 


FIG.  107.  —  Defining  elements  of  simple 
float-feed  carburetor. 


noise. 

4s6es/os  Covering 
Asbestos  Cover  Band. 


£xheust  from 
Engirt 


Outer  She// 


She// 


^Middle  She// 


FIG.  108.  —  Muffler. 


The  amount  of  gasoline  needed  to  run  the  engine  varies 
with  the  make  of  the  car.  Some  cars  will  run  from  20  to  25 
miles  on  a  gallon  of  gasoline,  while  others  will  run  only  ten 
miles. 


THE  AUTOMOBILE  277 

Ignition  system.  The  purpose  of  the  ignition  system  is  to 
explode  the  gases  in  the  cylinder  at  the  proper  time,  so  that 
the  piston  may  be  forced  down.  The  heat  to  ignite  the  gas 
is  furnished  by  an  electric  spark.  The  source  of  electricity 
may  be  either  dry  cells,  storage  batteries,  or  magnetos ;  or  a 
combination  may  be  used.  The  switch  that  regulates  the  time 
of  explosion  is  controlled  by  contact  with  the  camshaft, 
which  is  so  set  that  the  explosion  occurs  at  the  proper  time. 
A  part  of  the  ignition  system  is  an  induction  coil,  which  is  a 
device  by  means  of  which  a  current  of  sufficient  strength  is 
formed  to  cause  a  spark  in  the  cylinder.  The  spark  plug 
is  composed  of  two  points  separated  by  a  short  distance, 
across  which  the  current  jumps,  producing  the  spark  that 
sets  fire  to  the  gases. 

Lubricating  system.  In  order  to  prevent  friction  from 
wearing  out  the  parts  of  the  engine,  they  must  be  kept  sup- 
plied with  oil.  The  lubricating  system  commonly  used 
consists  of  a  tank  for  storing  the  oil,  a  kind  of  pump  to  force 
the  oil  to  the  bearing  parts,  and  piping  to  take  the  oil  from 
the  tank  to  the  pump  and  from  the  pump  to  the  engine. 
The  tank  is  large  enough  to  hold  one  or  two  quarts  of  oil, 
and  the  pump  is  worked  automatically  by  connection  with 
the  crank  shaft  or  other  part  of  the  engine. 

Cooling  the  engine.  The  combustion  of  gases  in  the  cylinder 
produces  a  large  amount  of  heat,  and  the  cylinder  would 
soon  become  heated  to  such  a  high  temperature  as  to  inter- 
fere seriously  with  the  working  of  the  engine.  So  some  de- 
vice must  be  used  to  keep  the  cylinder  from  getting  over- 
heated. This  is  accomplished  by  the  use  of  either  air  or 
water.  The  air-cooled  engines  are  constructed  in  such  a 
way  as  to  expose  a  large  surface  for  cooling.  In  most  cases 
fans  or  some  other  device  are  used  for  forcing  drafts  of  air 
against  the  cylinder. 

The  air  system  of  cooling  has  the  advantage  of  simplicity 
and  is  much  easier  to  operate,  especially  in  winter  when 


278  SCIENCE  OF  HOME  AND   COMMUNITY 

there  is  danger  that  water  will  freeze.  On  the  whole,  how- 
ever, the  air  system  is  much  less  effective  than  the  water 
system.  To  avoid  the  danger  of  overheating,  nearly  all 
makes  of  cars  use  the  water  system. 

In  the  water  system  of  cooling,  the  cylinder  is  surrounded 
by  a  jacket  kept  filled  with  water.  The  circulation  of  this 
water  is  maintained  in  either  of  two  ways,  the  natural  system 
or  the  pump  system.  In  the  natural  system,  the  water 
circulates  as  in  a  hot-water  heating  system,  described  on 
page  7,  the  hot  water  rising  and  the  cold  water  flowing  in 
to  take  its  place.  In  the  other  system,  the  water  is  forced 
around  through  the  tubes  by  means  of  pumps  operated 
automatically  by  connection  with  some  part  of  the  engine. 
The  water  is  cooled  by  passing  through  radiators  exposed 
to  air  and  containing  many  tubes  which  give  a  large  cooling 
surface.  The  air  is  forced  against  these  radiators  by  means 
of  fans.  In  winter  alcohol  is  added  to  the  water  to  prevent 
freezing. 

DEMONSTRATION  20 

Purpose.    To  show  how  the  gas  engine  works. 

Apparatus.  Two  large-mouth  bottles,  pan,  coffee  pot, 
Bunsen  burners,  small  gas  engine  or  model  of  one,  induction 
coil,  cells. 

Directions,  i.  To  show  the  need  of  a  mixture  of  gases  to  cause 
an  explosion.  Fill  an  ordinary  pan  about  a  third  full  of  water. 
Fill  one  large-mouth  bottle  with  water  and  another  half  full. 
Invert  them  both  in  the  pan  of  water.  Connect  a  piece 
of  rubber  tubing  with  the  gas  jet.  Put  the  other  end  over  the 
edge  of  the  pan  and  under  the  mouth  of  the  bottles.  Then  turn 
on  the  gas  till  the  water  is  forced  out  of  the  bottles.  Then 
turn  off  the  gas.  Take  out  the  bottles  and  put  a  piece  of  card- 
board over  the  mouth  of  each.  Bring  a  lighted  match  to  the 
mouth  of  the  bottles  after  taking  off  the  covers.  What  is  the 
difference  in  the  action  of  the  two?  What  does  this  show? 
Partially  fill  the  bottles  again  with  water  to  see  what  propor- 
tion of  air  and  gas  give  the  loudest  explosion.  If  illuminating 


THE   AUTOMOBILE  279 

gas  is  not  available,  hydrogen  gas  may  be  generated  by  using 
zinc  and  hydrochloric  acid. 

2.  To  show  that  this  explosion  has  the  power  to  do  work.     Cut 
a  hole  in  the  side  of  a  coffee  pot  near  the  bottom  big  enough 
to  admit  the  end  of   a  Bunsen   burner.     Halfway  up   on  the 
side  make  a  small  hole.     Turn  on  the  gas  and  bring  a  lighted 
match  near  the  small  hole.     Why  does  the  cover  fly  back? 
Close  the  cover  and  see  how  many  times  it  can  be  made  to  fly 
back.       Turn  off  the  gas  and  clean  out  the  products  of  combus- 
tion from  the  pot.     Then  try  the   experiment   again.     What 
do  the  results  show  ? 

3.  To  show  how  the  gas  is  ignited.     Set  up  an  induction  coil 
and  cells  and  show  the  formation  of  the  spark. 

4.  Run  a  small  gas  engine  with  illuminating  gas.     Notice 
carefully  how  each  part  works.     Or  make  a  study  of  a  model. 
Make  a  drawing  and  explain  the  use  of  the  various  parts. 

Other  devices.  Clutch.  The  clutch  is  a  device  by  means 
of  which  the  engine  may  be  allowed  to  run  alone  without 
moving  the  wheels  of  the  automobile.  This  serves  two  pur- 
poses. When  starting  the  car,  it  is  necessary  to  allow  the 
engine  to  get  full  speed  before  putting  on  the  load;  then 
after  the  engine  is  once  started,  the  clutch  may  be  gradually 
thrown  in  and  the  car  starts.  And  again,  when  it  is  desired 
to  stop  for  a  very  short  time,  the  clutch  may  be  thrown  out 
and  the  engine  need  not  be  stopped ;  this  saves  starting  the 
engine  again.  The  most  common  kind  of  clutch  is  the 
friction  type,  in  which  the  parts  are  held  so  closely  together 
by  springs  that  they  rotate  together.  The  tension  of  the 
springs  is  released  by  means  of  a  foot  pedal,  thus  allowing  the 
parts  to  operate  separately. 

Gear  box.  The  gear  box  is  a  mechanism  by  means  of 
which  the  speed  and  driving  power  of  the  engine  may  be 
changed.  These  are  spoken  of  as  the  high  and  low  gear. 
When  climbing  a  hill,  it  is  desirable  to  increase  the  power 
and  lessen  the  speed.  The  gear  box  contains  different 


280  SCIENCE  OF  HOME  AND   COMMUNITY 

combinations  of  gears,  which  are  controlled  by  a  lever. 
The  mechanism  for  reversing  the  engine  is  also  located  in 
the  gear  box. 

Power  transmission.  Power  may  be  transmitted  from 
the  gear  set  to  the  wheels  by  means  of  sprockets  and  chains, 
or  by  means  of  a  shaft  and  gears  on  the  rear  axle.  The  chain 
drive  is  often  used  on  large  motor  vehicles,  but  the  gear 
drive  is  used  largely  on  the  ordinary  cars.  This  has  the  ad- 
vantage over  the  chain  drive  that  it  is  inclosed  and  so  can 
easily  be  kept  lubricated  and  free  from  dirt. 

Lights.  Three  means  of  lighting  automobiles  have  been 
used :  kerosene,  gas,  and  electricity.  In  the  gas  systems, 
a  tank  containing  acetylene  gas  under  pressure  is  attached 
to  the  car.  Electricity  is  now  most  commonly  used.  This 
has  the  advantages  of  cleanliness,  reliability,  and  ease  of 
operation,  the  lights  being  turned  off  and  on  by  operating  a 
switch. 

Three  types  of  electric  lighting  systems  are  in  use:  that 
using  the  dynamo  or  magneto ;  that  using  the  storage 
battery;  and  that  using  both  the  dynamo  and  storage 
battery.  In  the  last  system,  the  current  to  the  lamps  is 
furnished  by  the  battery,  but  the  dynamo  keeps  the  battery 
charged.  This  combination  system  is  the  one  most  com- 
monly used. 

Means  of  controlling  automobiles.  The  engine  is  started 
either  by  hand  or  by  electricity.  At  first  the  clutch  is 
thrown  out  by  means  of  a  foot  pedal  and  then  allowed  to 
come  back  after  the  engine  starts.  The  direction  of  the  car 
is  controlled  by  the  st earing  wheel,  which  connects  with 
the  two  front  wheels.  The  speed  is  controlled  by  means  of 
two  levers  on  the  steering  wheel,  one  of  which  controls  the 
supply  of  gas  given  to  the  engine,  and  the  other  controls  the 
time  of  sparking.  In  some  cars  the  supply  of  gas  may  also 
be  controlled  by  a  foot  pedal.  The  speed  may  also  be  con- 
trolled by  changing  the  lever  in  the  gear  box.  The  rate  of 


THE  AUTOMOBILE 


281 


speed  is  indicated   by   a   speedometer,   and   the   distance 
traveled  is  registered  on  a  cyclometer. 

The  average  car  has' an  engine  of  from  25  to  50  horse  power, 
enabling  one  to  attain  a  speed  of  30  miles  an  hour  or  more. 
On  racing  cars,  engines  of  tremendous  horse  power  are  used. 
Speeds  have  been  attained  exceeding  that  of  the  locomotive. 
Special  racing  cars  have  traveled  at  the  rate  of  a  mile  in  less 
than  half  a  minute. 


Steering 
Wheel    ' 


FIG.  109.  —  Control  of  automobile. 

Stopping  the  car.  There  are  several  means  used  to  stop 
the  car:  shutting  off  the  supply  of  gasoline,  throwing  out 
the  clutch,  and  applying  the  brakes.  The  most  common 
kind  of  brake  is  a  band  brake,  which  works  on  the  hub  of 
the  rear  wheels.  This  is  operated  by  means  of  a  foot  pedal. 
The  brake  may  also  be  attached  to  a  drum  on  the  driving 
shaft.  Frequently  another  brake  is  provided,  known  as  the 
emergency  brake.  This  is  usually  operated  by  hand  by 
moving  a  lever. 

Warning  signals.  Warning  signals  may  take  a  great 
variety  of  forms ;  but  the  most  common  types  are  the  bulb 
horn  operated  by  hand,  the  exhaust  whistle,  which  is  at- 
tached to  the  exhaust  pipe  and  operated  by  the  escaping 


282  SCIENCE  OF  HOME   AND   COMMUNITY 

gas,  and  the  electric  horn,  operated  by  electricity.  In  the 
electric  horn  a  membrane  is  caused  to  vibrate  by  means  of 
a  cam  provided  with  many  points  and  rotated  by  a  motor. 


FIG.  no.  —  Shaft  brake  of  band  form. 

FIELD  EXERCISE  6 

Purpose.  To  study  the  parts  of  an  automobile  and  see  how 
it  is  run. 

Directions.  I.  Arrangements  should  be  made  with  some 
mechanic  in  a  garage  to  have  the  class  visit  the  shop  when  an 
auto  is  being  taken  apart  to  be  fixed.  The  uses  of  the  various 
parts  can  then  be  explained  to  the  members  of  the  class. 

2.  Arrangements  can  also  doubtless  be  made  with  some  of 
the  parents  of  the  members  of  the  class  who  own  an  auto,  to 
take  small  groups  on  an  auto  ride  and  explain  the  method  of 
running  the  car. 

SUPPLEMENTARY  QUESTIONS  FOR  CLASS  DISCUSSION 

1.  Name  all  the  uses  that  you  have  seen  made  of  automo- 
biles. 

2.  Which  is  more  useful,  the  auto  or  electric  trolley  car? 


THE  AUTOMOBILE  283; 

3.  Which  has   more   advantages,   the   electric   auto   or   the 
gasoline  auto  ? 

4.  How  does  the  gasoline  engine  differ  from  the  steam  engine  ?' 

5.  What  purpose  does  each  of  the  following  systems  serve- 
in  the  auto :  the  carburetion  system,  the  ignition  system,  and. 
the  cooling  system? 

6.  Explain  how  the  engine  works. 

7.  Which  is  the  best  method  of  lighting  the  auto? 

8.  How  does  the  chauffeur  control  the  car? 

9.  What  devices  are  provided  for  preventing  accidents  ? 

REFERENCES 

Baker,  Boy's  Book  of  Inventions,  Doubleday  Page  and  Co.,  New 

York  City.     Chap.  4. 
Cressey,   Discoveries  'and   Inventions  of  the    Twentieth   Century,. 

E.  P.  Button  Co.,  New  York  City.     Chap.  14. 
Darrow,  Th?  Boys'  Own  Book  of  Great  Inventions,  The  Macmillan 

Co.,  New  York  City.     Chap.  12. 
Doubleday,   Stories    of  Inventors,    Doubleday  Page   Co.,    New 

York  City.     Pages  67-85. 
Harper's  Machinery  Book  for  Boys,  Harper  Bros.,  New  York: 

City.     Chap.  18. 
Holland,  Historic  Inventions,  G.  W.  Jacobs  Co.,  Philadelphia.- 

Chap.  16. 
Maule,   Boys'   Book  of   New  Inventions,  Grosset  and  Dunlap,, 

New  York  City.     Chap.  10. 
Williams,  How  It  Works,  T.  Nelson  and  Sons,  New  York  City., 

Chap.  4. 


CHAPTER   XIX 
THE   STEAMBOAT 

1.  In  what  ways  are  the  means  of  travel  on 
water  now  in  use  better  than  they  were  when  Co- 
lumbus discovered  this  continent  ? 

2.  How  is  the  submarine  made  so  that  it  is  able 
to  travel  under  water  ? 

Early  types  of  boats.  Probably  the  'first  boat  used  by 
primitive  man  was  a  log,  which  may  have  been  propelled 
by  using  a  branch  for  an  oar.  From  this  two  types  of  boats 
developed.  One  was  the  dugout,  made  by  digging  away 
the  center  of  a  log.  Improving  on  this  type,  men  later  con- 


FIG.  in.  —  The  first  boat. 

structed  canoes  made  of  bark  or  other  light  material.  The 
other  early  form  was  the  raft,  made  by  fastening  several 
logs  together.  At  first  the  rafts  were  propelled  by  hand ; 
later,  sails  were  attached  to  them. 

Eventually  the  raft  developed  into  a  large  boat,  made  by 
fastening  planks  and  logs  together  to  give  it  a  spoon  shape. 
These  early  boats  were  propelled  by  both  oars  and  sails. 
At  first  there  was  no  rudder.  About  1 100  B  .c.  the  first  rudder 

284 


THE   STEAMBOAT  285 

appeared  in  the  form  of  an  oar  projecting  from  the  stern  of 
the  boat.  This  type  of  rudder  was  used  for  many  hundreds 
of  years. 

The  best  type  of  boat  of  ancient  times  was  the  Roman 
galley.  Some  of  the  galleys  of  this  time,  about  100  A.D., 
were  400  feet  long.  Oars  were  depended  on  chiefly  for  pro- 
pelling the  boat.  In  some  of  the  large  boats  several  hundred 
rowers  were  employed.  Sometimes  there  were  three  tiers 
of  oars,  one  above  the  other. 

During  the  next  few  centuries  little  progress  was  made  in 
boat  building.  Gradually  less  reliance  was  placed  on  oars 
and  more  on  sails,  until  the  sails  replaced  the  oars  entirely ; 
so  that  the  boats  of  this  time  could  be  called  sailing  ships. 
The  rudder  was  improved  and  fastened  to  the  boat  and 
worked  by  means  of  a  tiller. 

About  the  middle  of  the  thirteenth  century  the  compass 
was  first  used  as  a  guide  for  steering  the  boat.  Before  this, 
sailors  had  steered  at  night  by  the  north  star.  In  cloudy 
weather  they  were  easily  lost.  The  use  of  the  compass 
enabled  the  sailors  to  undertake  much  longer  journeys  than 
they  had  ever  dared  to  try  before.  Without  the  aid  of  the 
compass  probably  the  New  World  would  not  have  been  dis- 
covered at  the  time  it  was  by  the  people  of  Europe. 

The  first  steamboat.  The  next  great  development  was 
the  application  of  steam  power  to  the  propulsion  of  boats. 
The  first  boat  to  be  propelled  by  steam  was  made  by  an 
American  named  James  Ramsey.  In  1786  this  boat  was 
driven  at  the  rate  of  five  miles  an  hour.  This  was  propelled 
by  means  of  a  piston  working  in  a  cylinder.  When  the  piston 
was  raised,  the  cylinder  was  filled  with  water,  and  when  the 
piston  was  pushed  down  the  water  was  forced  out,  and  the 
reaction  of  this  against  the  water  in  the  river  caused  the 
boat  to  move  ahead. 

In  1787  another  American,  named  John  Fitch,  made  a 
boat  in  which  the  oars  were  worked  by  a  steam  engine.  A 


286  SCIENCE   OF  HOME  AND    COMMUNITY 

speed  of  three  or  four  miles  an  hour  was  attained.  Both 
of  these  were  interesting  experiments,  but  neither  was  a 
success  commercially. 

Robert  Fulton's  "  Clermont."  The  first  really  successful 
steamboat  was  built  by  Robert  Fulton.  In  1807  his 
steamboat,  the  Clermont,  made  a  trip  on  the  Hudson 
from  New  York  to  Albany  —  a  distance  of  150  miles  — 
and  return  in  62  hours.  This  trip  was  regularly  made  by 
sailing  packets  in  about  four  days.  The  Clermont  was  pro- 
pelled by  means  of  paddle  wheels,  which  were  fifteen  feet  in 
diameter,  one  on  each  side  of  the  boat,  and  turned  by  a 


FIG.  112.  —  Fulton's  Clermont,  the  first  steamboat. 

steam  engine.  The  boat  was  130  feet  long.  The  Clermont 
continued  to  make  regular  trips  between  these  cities  and  to 
take  passengers. 

Trans- Atlantic  steamboats.  Other  steamboats  were  soon 
built  in  other  sections  of  the  country,  and  twelve  years  later 
the  steamship  Savannah,  using  both  steam  and  sails,  crossed 
the  Atlantic  Ocean  in  26  days.  The  first  steamboat  to  cross 
the  Atlantic  using  steam  all  the  way  was  the  Royal  Williams, 
which  crossed  from  Nova  Scotia  to  the  Isle  of  Wight  in 
17  days. 

The  next  great  improvement  in  the  steamboat  was  the 
invention  by  John  Ericsson  of  the  screw  propeller.  This 
is  a  wheel  entirely  immersed  in  water  and  fastened  at  the 


THE   STEAMBOAT 


287 


stern  of  the  boat.  Its  blades  are  placed  in  such  a  way  that 
as  they  rotate  and  push  against  the  water  they  force  the 
boat  ahead.  The  first  steamboat  using  a  screw  propeller 
crossed  the  Atlantic  in  1839.  Since  that  time,  there  have 
been  many  wonderful  improvements  in  the  ocean  steamship. 
The  first  ocean  steamers  were  made  of  wood.  Later  iron 
was  used.  The  first  iron  steamboat  crossed  the  Atlantic 
in  1850.  About  25  years  later,  steel  took  the  place  of  iron, 
and  to-day  our  great  Atlantic  steamships  are  made  entirely 
of  steel. 


FIG.  113.  —  A  modern  steamship. 

Lusitania.  Such  improvements  have  been  made  in  the 
modern  trans-Atlantic  steamships  that  they  are  floating 
hotels  with  all  the  comforts  and  conveniences  that  are  ob- 
tainable on  land.  Some  have  such  conveniences  as  drawing 
rooms,  smoking  rooms,  reading  and  writing  rooms,  veranda 
cafes,  and  even  gymnasiums  and  swimming  pools.  One 
of  the  largest  of  these,  the  ill-fated  Lusitania,  that  was  sunk 
by  a  German  submarine,  was  790  feet  long  and  88  feet  wide. 
It  was  provided  with  engines  of  a  total  horse  power  of 
70,000,  which  gave  the  steamer  a  high  rate  of  speed.  She 
held  the  record  for  speed,  having  made  632  knots  in  24 
hours,  an  average  of  26  knots  or  30  miles  in  an  hour.  She 


288 


SCIENCE  OF  HOME  AND   COMMUNITY 


made  the  entire  voyage  across  the  Atlantic  in  4  days, 
20  hours,  and  22  minutes,  averaging  28.5  miles  per  hour. 
Accommodations  were  provided  for  several  thousand  people. 
Provisions  for  a  trip  across  the  ocean.  Some  idea  of  the 
preparations  necessary  for  a  trip  across  the  ocean  may  be 
obtained  from  the  following  figures  showing  just  a  few  items 
of  food  needed  by  this  ship  for  a  round  trip:  80  boxes  of 
oranges,  1000  pounds  of  tea,  1800  pounds  of  coffee,  10,000 
pounds  of  sugar,  210  barrels  of  flour,  8000  pounds  of  cereals, 
3000  gallons  of  milk,  40,000  eggs,  28  tons  of  potatoes,  2000 
chickens,  5500  pounds  of  butter,  17,000  pounds  of  mutton, 
45,000  pounds  of  beef.  This  food  was  cooked  in  kitchens 
provided  with  steam  ovens  and  electric  heating  devices. 

Steam  turbine.  In  recent  years  there  has  been  developed 
a  new  type  of  steam  engine  called  the  turbine,  that  is  being 

much  used  on  steamships.  It 
is  much  like  a  water  wheel, 
which  is  turned  by  the  force  of 
the  water  striking  against  its 
paddles.  In  the  steam  turbine 
the  steam  is  led  through  small 
nozzles  and  caused  to  strike 
against  many  blades  on  a  re- 
volving drum.  The  steam  is 
under  enormous  pressure,  and 
as  it  strikes  against  these  blades 
it  causes  the  drum  to  revolve 
at  a  tremendous  speed  (figure  114).  There  are  several  series 
of  these  blades,  so  arranged  that  the  steam  rebounds  from 
one  set  to  the  next,  the  steam  being  used  repeatedly. 

These  turbines  are  now  being  used  on  such  large  steam- 
ships as  the  Mauretania,  as  it  is  found  that  they  have  the 
following  advantages  over  the  ordinary  steam  engine: 
(i)  There  is  no  vibration,  thus  allowing  the  boat  to  travel 
smoothly  without  unpleasant  jarring.  (2)  They  occupy 


FlG.  114.  —  Steam  turbine  with  one 
set  of  nozzles. 


THE   STEAMBOAT  289 

less  space.  (3)  They  are  more  economical  at  high  speeds. 
(4)  They  are  more  easily  tended  and  require  fewer  repairs. 

DEMONSTRATION  21 

Purpose.     To  make  a  simple  steam  turbine. 

Apparatus.  Flask,  rubber  stopper  with  one  hole,  glass 
tubing,  toy  windmill. 

Directions,  i.  To  make  a  toy  windmill,  take  a  piece  of 
paper  about  6  inches  square  and  cut  from  each  corner  in- 
ward nearly  to  the  center.  Fold  over  every  other  point.  Pass 
a  pin  through  these  four  points,  through  the  center  of  the  paper, 
and  then  into  a  wooden  handle. 

2.  Heat  a  piece  of  glass  tubing  and  draw  it  out  nearly  to  a 
point.  Break  it  off,  leaving  a  very  small  hole.  Put  this  tube 
in  th,e  hole  of  the  rubber  stopper  and  then  insert  the  stopper 
in  a  flask  so  that  the  small  point  is  uppermost.  Fill  the  flask  a 
third  full  of  water.  Heat  the  flask  till  the  water  boils  vigorously. 
Then  hold  the  windmill  over  the  glass  tube  where  the  steam  is 
escaping. 

Change  in  a  century.  About  one  hundred  years  after 
the  Clermont  had  made  its  first  trip  at  the  rate  of  5  miles  an 
hour,  another  boat,  a  yacht  called  the  Arrow,  traveled  a 
mile  over  the  same  course  in  i  minute  and  32  seconds,  which 
is  at  the  rate  of  46  miles  an  hour.  From  5  miles  an  hour  to 
46  miles  an  hour  represents  the  progress  made  in  one  hun- 
dred years. 

How  vessels  are  guided.  Compass.  In  the  earliest  times 
men  did  not  dare  to  venture  far  from  land  but  steered  by  land- 
marks, by  the  sun,  and  perhaps  by  the  flight  of  birds,  and  on 
clear  nights  by  the  stars.  The  compass  was  first  used  as  a 
guide  in  steering  ships  between  noo  and  1200  A. D.  In  its 
first  form  it  was  a  needle  in  a  straw  floating  on  water.  About 
1360  the  needle  was  mounted  on  a  pivot  and  inclosed  in  a 
box  as  it  is  now  used.  A  compass  is  a  magnet  mounted  so 
that  it  can  turn  easily,  and  it  always  takes  a  north  and  south 
u 


2 90  SCIENCE  OF  HOME  AND   COMMUNITY 

position.  The  power  of  a  magnet  to  take  this  position  was 
not  known  till  the  end  of  the  eleventh  century,  and  then  only 
to  a  few  learned  men.  They  did  not  think  it  safe  to  tell  the 
•common  people  about  its  use  in  steering  ships,  for  fear  they 
would  be  considered  magicians,  so  it  was  a  long  time  after, 
probably  over  a  hundred  years,  before  the  compass  was  in 
'Common  use. 

The  tendency  of  the  compass  to  point  north  and  south  is 
•explained  by  saying  that  the  whole  earth  acts  like  a  huge 
magnet  with  its  two  magnetic  poles  near  the  geographic  poles. 
The  compass  points  to  the  magnetic  north  pole  and  not  to 
the  geographic  north,  so  that  for  most  sections  of  the  earth  a 
•certain  number  of  degrees  must  be  added  to  or  subtracted 
from  the  reading  of  the  compass,  to  get  the  true  north.  As 
one  passes  east  or  west  these  corrections  vary.  Since  in  re- 
cent years  so  much  steel  has  been  used  in  the  construction 
of  steamships,  it  is  found  that  the  compass  is  influenced 
by  the  mass  of  iron  near  it.  For  these  two  reasons, 
therefore,  some  substitute  for  the  compass  in  guiding  ships 
has  been  sought. 

LABORATORY  EXERCISE  28 

Purpose.     To  study  the  action  of  the  compass. 

Apparatus.  Compass,  two  darning  needles,  knitting  needle, 
cork,  magnet. 

Directions,  i.  Magnetize  a  knitting  needle  by  rubbing  an 
end  of  the  needle  on  one  end  of  the  magnet,  and  the  other  end 
of  the  needle  on  the  other  end  of  the  magnet.  Fold  a  piece  of 
paper  about  one  inch  square,  diagonally.  Place  the  needle 
at  its  middle  in  the  crease  of  paper  and  suspend  the  paper  by 
means  of  a  fine  thread.  In  what  position  does  the  needle  come 
to  rest?  Compare  with  the  compass.  Move  the  needle,  and 
try  several  times.  Does  it  always  come  to  rest  in  the  same 
position  ? 

2.  Magnetize  a  large  darning  needle  by  rubbing  the  point  on 
the  north  pole  of  a  magnet  and  the  eye  end  on  the  south  pole, 


THE  STEAMBOAT 


291 


Magnetize  another  needle  by  rubbing  the  point  on  the  south 
pole  and  the  eye  end  on  the  north  pole  of  the  magnet.  Cut 
two  thin  pieces  of  cork  from  a  stopper.  Float  the  corks  in  a 
pan  of  water.  Put  a  needle  on  each  cork.  In  what  position 
do  the  needles  come  to  rest?  Do  the  points  of  both  needles 
point  in  the  same  direction  ?  Can  you  explain  ? 

3.  Set  the  compass  on  a  level  table  and  notice  the  direction 
in  which  the  needle  points.  Place  pieces  of  iron  and  steel  on 
the  table  near  and  see  if  the  needle  is  affected.  Try  a  magnet. 

Gyro-compass.  Recently  there  has  been  invented  a  new 
type  of  compass,  called  the  gyro-compass,  which  is  being 

G/ass 


Compass 
' 


•Mercury 


Gyrostat 


FIG.  115.  —  Section  of  gyro-compass. 

•used  commonly,  especially  on  battleships.  The  gyroscope 
is  a  wheel  mounted  on  an  axle  inside  of  a  frame,  which  tends 
to  rotate  in  the  same  plane  in  which  it  started.  If  the  wheel 
is  a  large  one,  the  strength  of  a  man  is  not  enough  to  change 
its  plane  of  rotation.  In  the  gyro-compass  the  wheel  is 
caused  to  rotate  in  a  north  and  south  plane  at  a  high  rate  of 
speed  by  means  of  a  motor.  The  gyroscope  is  floated  in  a 
bowl  containing  mercury,  so  that  the  wheel  keeps  rotating 


292  SCIENCE  OF  HOME  AND   COMMUNITY 

in  a  north  and  south  plane  regardless  of  any  motion  of  the 
ship.  The  top  is  covered  with  glass,  and  on  this  is  a  dial 
showing  the  points  of  the  compass.  Other  dials  may  be 
placed  in  any  part  of  the  ship  and  by  means  of  electrical 
connections  with  the  gyroscope  the  true  readings  are  indi- 
cated on  these  dials. 

LABORATORY  EXERCISE  29 

Purpose.     To  see  how  a  gyroscope  works. 

Apparatus.     Toy  gyroscope. 

Directions.  Set  the  gyroscope  spinning  by  means  of  a  string. 
Try  placing  the  gyroscope  in  a  great  many  positions,  as  on  the 
edge  of  a  tumbler,  on  a  string,  on  the  tip  of  a  pencil,  on  the  end 
of  the  finger  with  the  axis  horizontal.  How  could  this  be  used 
to  guide  vessels? 

Protection  from  accidents.  In  order  to  assure  the  safety 
of  the  large  ocean  ships,  they  are  provided  with  a  number 
of  separate  water-tight  compartments,  so  that  if  by  accident 
water  should  enter  one,  it  cannot  flood  the  others.  As  a 
protection  against  icebergs,  an  instrument  called  a  frigidom- 
eter  is  used.  This  consists  of  a  special  thermometer  placed 
near  the  forward  end  of  the  ship,  in  a  vessel  through  which 
sea  water  passes.  The  lowering  of  the  temperature  may 
indicate  the  presence  of  icebergs.  This  thermometer  is 
connected  with  an  indicator  on  the  bridge.  This  can  be 
so  set  that  when  a  certain  temperature  is  registered  by  the 
thermometer,  an  electric  gong  rings  and  a  red  light  shows 
as  a  warning  to  the  one  on  watch.  Protection  from  fire  is 
assured  by  the  use  of  steel  instead  of  wood  in  the  construc- 
tion of  the  ship. 

Protection  from  rocks.  Protection  from  dangerous  rocks 
and  coasts  is  assured  by  signals  conveyed  under  water. 
A  bell  is  submerged  under  water  over  the  dangerous  rocks 
and  the  strokes  are  controlled  from  a  shore  station  or  from 
a  lightship  by  means  of  electricity  or  compressed  air.  The 


THE   STEAMBOAT  293 

different  bells  can  be  distinguished  by  the  varying  numbel 
of  strokes  and  the  interval  between.  The  receiving  apparatus 
consists  of  water  tanks  about  two  feet  square  fastened  to 
the  ship  below  the  water  line.  Each  tank  contains  a  micro- 
phone which  is  connected  by  means  of  wires  with  a  tele- 
phone in  the  pilot  house.  By  this  means  the  pilot  can  hear 
the  strokes  of  the  bell  and  can  tell  from  their  number  and 
intervals  the  exact  locality.  These  signals  operate  up  to 
fifteen  or  twenty  miles.  They  operate  regardless  of  fog  01 
any  other  conditions  of  weather.  They  have  already  beer 
the  means  of  saving  many  lives  and  thousands  of  dollars' 
worth  of  property. 

Why  a  boat  floats.  When  a  boat  is  made  of  wood  it  is  not 
difficult  to  understand  why  it  floats;  but  when  boats  are 
made  of  a  heavy  substance  like  steel,  it  is  not  so  easy  to 
understand.  Whether  a  body  will  float  or  sink  depends  01? 
its  specific  gravity,  which  means  the  weight  of  a  body  com- 
pared  with  water.  A  body  that  weighs  the  same  as  an  equal 
volume  of  water  is  said  to  have  a  specific  gravity  of  i .  If  it 
weighs  twice  as  much,  it  has  a  specific  gravity  of  2  ;  if  half 
as  much,  a  specific  gravity  of  .5. 

A  body  that  has  a  specific  gravity  of  less  than  i  floats; 
one  that  has  a  specific  gravity  of  more  than  i  sinks,  when 
placed  in  water.  Now  when  a  piece  of  steel  is  so  much 
heavier  than  water,  how  is'  it  that  a  boat  made  of  steel 
floats?  The  explanation  is  that  a  large  amount  of  air  is 
inclosed  within  the  steel  sides  of  the  boat,  and  the  specific 
gravity  of  the  steel  and  air  combined  is  less  than  i ;  that  is 
to  say,  the  whole  volume  is  lighter  than  an  equal  volume  of 
water. 

LABORATORY  EXERCISE  30 

Purpose.    To  learn  why  a  boat  flpats. 

Apparatus.  Spring  balance,  stone,  overflow  can,  catch 
bucket,  wooden  cylinder  tc  fit  overflow  can,  egg,  salt,  shot, 
test  tube. 


294  SCIENCE  OF  HOME  AND   COMMUNITY 

Directions,  i.  To  show  the  buoyant  force  of  water  on  a 
sinking  body,  tie  a  string  to  a  stone  and  weigh  it  in  air  by  means 
of  a  spring  balance.  Submerge  the  stone  in  water  and  weigh 
it.  How  much  has  it  lost  ?  To  what  is  this  loss  due  ? 

2.  To  show  the  buoyant  effect  of  water  on  a  floating  body, 
fill  the  overflow  can  as  full  of  water  as  possible.     Weigh  the 
catch  bucket.     Weigh   the  wooden  cylinder.     Place  it   on  the 
surface  of  the  water  in  the  overflow  can  and  catch  the  overflow 
in  the  catch  bucket.     Find  the  weight  of  the  water  in  the  catch 
bucket.     How  does  this  compare  with  the  weight  of  the  block 
of  wood  ? 

3.  Put  some  shot  in  a  test  tube  and  float  the  tube  in  a  dish 
of  water.     Glass  and  shot  are  both  heavier  than  water.     Why 
then  does  the  tube  float?     Why  do  steel  ships  float?     Catch 
the  overflow  as  in  the  previous  experiment  and  compare  with 
the  weight  of  the  tube  and  shot.     Add  more  shot.     What  hap- 
pens   to    the    tube?     Remove    some    shot.     What    happens? 
What  fact  does  this  illustrate  about  the  loading  and  unloading 
of  a  boat  ? 

4.  To  show  the  difference  in  the  buoyant  force  of  fresh  and 
salt  water,  put  an  egg  in  a  dish  of  fresh  water.     What  happens  ? 
Put  the  egg  in  a  strong   solution    of  salt  and  water.     What 
happens?     What   causes   the   difference?     In   which   body   of 
water  would  a  boat  sink  deeper,  in  the  Great  Lakes  or  the  At- 
lantic Ocean?     Why? 

Submarines.  During  the  European  War  our  attention 
was  specially  called  to  submarines  on  account  of  the  de- 
structive use  to  which  they  were  put.  This  use  of  the  sub- 
marine was  especially  brought  home  to  the  American  people 
when  the  Lusitania  was  sunk  in  1915,  killing  more  than  a 
thousand  people,  including  many  Americans.  Some  Ger- 
man submarines  crossed  the  ocean  and  came  to  an  American 
port  bringing  merchandise.  The  use  that  has  been  made 
of  these  submarines  shows  how  well  perfected  they  have 
become..  It  is  a  possibility  of  the  near  future  that  one  may 
travel  across  the  ocean  in  a  submarine  submerged  all  the 


THE  STEAMBOAT  295 

way,  and  may  thus  avoid  the  dangers  and  inconveniences 
of  storms.  It  will  be  interesting  to  go  back  a  number  of 
years  and  trace  the  history  of  the  submarine  from  its  early 
stages. 

Submarines  in  the  Revolutionary  War.  During  the  Revo- 
lutionary War,  David  Bushnell  made  an  attempt  with  a 
submarine  to  blow  up  a  British  frigate  in  New  York  harbor. 
He  actually  succeeded  in  getting  under  one  of  the  warships 
with  a  magazine  of  powder ;  but  in  trying  to  fasten  this  to 
the  vessel  by  means  of  a  screw,  he  struck  it  against  a  bar  of 


'"^M^^^^i^^^^^mj&sm 


FIG.  1 1 6.  —  A  modern  submarine. 

iron.  While  trying  to  find  another  place,  he  drifted  away 
from  the  ship  and  could  not  find  it  again. 

Robert  Fulton  directed  his  attention  to  submarines  about 
the  year  1800.  His  experiments  were  partially  successful 
for  he  constructed  a  submarine"  which  descended  to  a  depth 
of  twenty-five  feet  and  remained  three  hours.  He  also 
showed  how  it  was  possible  to  use  a  submarine  to  blow  up 
other  boats  in  time  of  warfare. 

Submarines  in  the  Civil  War.  We  hear  again  of  sub- 
marines during  the  Civil  War,  when  the  Confederates  con- 
structed submarine  boats  called  "  Davids."  One  of  these 
was  successful  in  sinking  one  of  the  United  States  steam- 
ships, the  Hoosatonic,  by  means  of  a  torpedo.  The  sub- 
marine itself,  however,  was  disabled  by  the  explosion  and 
sank  to  the  bottom  with  its  crew. 

Holland  submarine.  The  first  really  successful  submarines 
were  built  by  Mr.  Holland  during  the  nineties.  In  1892  the 


*yd  SCIENCE  OF  HOME  AND   COMMUNITY 

United  States  Government  made  an  appropriation  to  be 
used  for  the  construction  of  submarines  for  the  navy,  and 
decided  to  adopt  the  Holland  type.  The  first  Holland  was 
completed  as  a  torpedo  boat  in  1900.  These  have  been 
greatly  improved  and  have  been  adopted  by  the  more  impor- 
tant navies  of  the  world. 

How  they  rise  and  sink.  Submarines  are  now  made  so 
that  they  can  run  either  on  the  surface  or  submerged.  They 
are  made  to  sink  by  admitting,  water  to  tanks,  and  can  be 
made  to  dive  by  the  action  of  the  propeller  and  a  horizontal 
rudder.  They  are  made  to  rise  again  by  pumping  out  the 


Cap  of 
Torpedo 

Tubes 
pedo  Tube 
Gasotene  Tanks 
eries 
Redder  Jlfatn    Baf/ast  Tanks'  ^C/rcu/ar  Jfuoyoncjr  Tank 

FIG.  117.  —  Sectional  view  of  submarine  (Holland  type). 

water.  The  depth  to  which  they  sink  is  indicated  by  means 
of  gauges.  The  shell  of  the  boat  is  made  of  strong  steel  so 
as  to  withstand  the  tremendous  pressure  of  the  water  far 
below  the  surface. 

DEMONSTRATION  22 

Purpose.  To  see  how  the  submarine  is  made  to  rise  and  sink. 

Apparatus.  Large-mouth  bottle,  rubber  stopper  with  two 
holes,  glass  tubing,  and  rubber  tube. 

Directions.  Fill  the  bottle  with  water.  Push  a  piece  of 
glass  tubing  through  one  of  the  holes  in  the  rubber  stopper. 
Push  one  end  of  the  rubber  tubing  over  the  glass  tube.  Put 
the  stopper  in  the  bottle  and  put  the  bottle  in  a  dish  of  water. 
Blow  through  the  rubber  tubing  till  the  water  is  forced  out  of 
the  bottle.  What  happens  to  the  bottle?  Why?  Fill  the 


THE   STEAMBOAT  297 

bottle  again  with  water  and  put  it  in  the  dish.     What  happens? 

Why? 

Some  of  the  latest  submarines  are  several  hundred  feet 
long.  They  can  travel  when  submerged  n  knots  an  hour, 
and  on  the  surface  17  knots;  they  are  able  to  travel  140 
miles  under  water  and  5000  miles  on  the  surface.  One  type 
is  2 1  feet  wide,  has  accommodations  for  2  7  men,  and  carries 
provisions  to  last  30  days.  During  the  European  War 
great  improvements  in  submarines  were  made  by  the  Ger- 


FIG.  1 1 8.  —  Submarine  diving. 

mans,  but  the  exact  details  of  construction  are  not  yet 
generally  known. 

How  the  submarine  is  propelled.  Two  sources  of  power 
are  used  for  propelling  the  boat.  When  the  boat  is  on  the 
surface,  a  gasoline  or  oil  engine  is  used  to  run  the  boat,  and 
this  also  runs  a  dynamo  which  charges  at  storage  battery. 
When  the  boat  is  under  water,  the  gasoline  engine  is  shut  off, 
and  the  propeller  is  turned  by  a  motor  run  by  electricity 
from  the  storage  battery.  This  also  furnishes  electricity 
for  lighting  the  boat  and  for  cooking. 


298 


SCIENCE  OF  HOME  AND   COMMUNITY 


In  order  to  supply  air  for  the  passengers,  tanks  of  com- 
pressed air  are  carried.  In  submarines  used  for  war  pur- 
poses compressed  air  is  also  used 
to  work  machines  to  discharge 
torpedoes.  These  are  arranged 
so  that  they  can  be  discharged  at 
an  enemy's  ship  a  long  distance 
away. 

Periscope.  To  enable  the  peo- 
ple in  a  submarine  to  see  the 
surroundings  on  the  surface  of 
the  water,  a  periscope  is  used. 
This  consists  of  a  long  tube  reach- 
ing to  the  surface  of  the  water 
and  containing  mirrors  so  ar- 
ranged that  one  looking  through 
a  telescope  in  the  boat  is  able  to 
see  what  is  in  front  of  the  peri- 
scope. It  can  be  turned  so  as  to 
face  any  part  of  the  horizon. 

SUPPLEMENTARY  QUESTIONS  FOR 
CLASS  DISCUSSION 


Courtesy  of  Harper  &  Brothers 
FIG.  119. — Periscope  of  submarine. 


I .  Summarize  briefly  the  changes 
that  have  taken  place  in  the  steam- 
boat during  the  last  hundred  years. 

2.  What  conveniences  are  found  on  a  modern  trans- Atlantic 
steamship  ? 

3.  How  does  the  steam  turbine   differ  from  the  ordinary 
steam  engine  used  on  the  locomotive  ? 

4.  Why  is  the  gyro-compass  taking  the  place  of  the  ordinary 
compass  as  a  means  of  guiding  ships  ? 

5.  What  provisions  have  steamships  as  a  protection  against 
accidents  ? 

6.  What  uses  can  be  made  of  the  submarine  boat  in  times  of 
peace  ? 


THE   STEAMBOAT  299 

7.    What  features  are  found  on  the  submarine  that  are  not 
found  on  the  ordinary  boat  ? 

REFERENCES 

Cressey,   Discoveries  and   Inventions  of  the    Twentieth   Century, 

E.  P.  Button  Co.,  New  York  City.    Chap.  15  and  pages  328- 

333  (Submarines). 
Darrow,  The  Boys'  Own  Book  of  Great  Inventions,  Macmillan  Co., 

New  York  City.     Chapter  10  (Submarines). 
Doubleday,    Stories    of    Inventors,    Doubleday    Page    and    Co., 

New  York  City.     Pages  85-97  and  153-181  (Submarines). 
Holland,  Historic  Inventions,    G.  W.  Jacobs  Co.,    Philadelphia. 

Chap.  7. 
Howden,  Boys'  Book  of  Steamships,  McClure  Co.,  New  York 

City. 
Johnson,  Modern  Inventions,   F.  A.  Stokes  Co.,  New  York  City. 

Chap.  2  (Submarines). 
Maule,   Boys'   Book  of    New  Inventions,  Grosset  and  Dunlap, 

New  York  City.     Chap.  8  (Turbines). 


CHAPTER  XX 
AIRSHIPS  AND  AIRPLANES 

1.  What  progress  has  been  made  in  the  last 
twenty  years  in  the  development  of  air  navigation? 

2.  How  do  the  airship  and  the  airplane  differ  in 
their  construction  and  the  method  by  which  they 
are  kept  in  the  air  ? 

During  the  European  War  frequent  references  were  made 
in  the  newspapers  to  the  use  that  was  being  made  of  air- 
planes and  airships,  especially  of  the  Zeppelins  in  their  air 
raids  on  England.  Some  idea  of  the  distance  these  airships 
can  travel  is  given  by  the  fact  that  frequent  raids  were  made 
on  London,  showing  that  these  ships  can  travel  from  Ger- 
many to  London  and  return  without  alighting. 

In  our  own  country,  the  United  States  Government  is 
authorized  by  Congress  to  spend  $300,000  annually  for 
carrying  mails  by  air  routes.  During  the  Mexican  disturb- 
ance, when  American  soldiers  were  camping  in  Mexico,  mail 
was  taken  almost  daily  from  Columbus,  New  Mexico,  to 
General  Pershing's  headquarters,  a  distance  of  over  400 
miles. 

During  the  summer  of  1918  a  regular  aerial  mail  route  was 
established  between  New  York  and  Washington,  and  between 
New  York  and  Chicago.  (See  figure  120.)  Regular  trips  are 
made  each  way  daily  except  on  Sunday.  The  trip  from  New 
York  to  Washington  (225  miles),  which  is  made  by  the  trains 
in  6  hours,  is  made  by  the  airplanes  in  two  and  a  half  or 
three  hours.  The  trip  between  New  York  and  Chicago  (850 

300 


AIRSHIPS  AND  AIRPLANES 


3OI 


miles),  which  is  made  by  the  fastest  trains  in  21  hours,  is 
made  by  the  airplanes  in  9  hours.  Plans  are  being  made  to 
extend  this  service  to  other  cities. 

It  has  been  suggested  that  further  application  of  airplanes 
may  be  made  by  using  hydroplanes  along  lakes  and  rivers  to 
patrol  forests  so  as  to  enable  the  foresters  to  more  efficiently 
control  forest  fires. 

Let  us  notice  the  early  attempts  that  were  made  to  navi- 
gate the  air  and  see  what  progress  has  been  made  up  to  the 


FIG.  120.  —  One  of  Uncle  Sam's  new  aerial  postmen,  Lieut.  Culver,  who  started 
from  Washington  during  the  summer  of  1918  in  the  first  aerial  mail  flight. 


present  time,  especially  the.  very  remarkable  progress  within 
the  last  ten  years. 

Early  history  of  balloons.  The  first  experiments  with 
balloons  were  carried  on  in  France.  The  first  man  to 
ascend  in  a  balloon  was  M.  de  Rozier,  who  in  1783  rose  to  a 
height  of  about  84  feet,  the  balloon  being  held  captive  with 
ropes.  This  was  made  to  rise  by  building  a  fire  on  a  grate 
situated  at  the  bottom  of  the  balloon,  and  as  the  air  became 
heated  the  balloon  rose  bearing  with  it  M.  de  Rozier,  who 


302  SCIENCE  OF  HOME  AND   COMMUNITY 

kept  the  balloon  in  the  air  for  about  five  minutes  by  throw- 
ing straw  and  wood  on  the  fire. 

About  a  month  later  another  ascent  was  made  by  two 
men,  and  the  balloon  was  allowed  to  go  free  with  the  wind. 
The  men  descended  about  five  miles  from  the  starting  place, 
the  journey  taking  about  2  5  minutes. 

In  less  than  a  month  after  this,  another  ascent  was  made 
by  two  other  Frenchmen  in  a  balloon  filled  with  hydrogen 
gas.  The  journey  lasted  about  an  hour  and  a  half  and  the 
men  landed  about  thirty  miles  from  the  place  from  which 
they  started.  The  first  ascent  in  America  was  made  during 
the  last  of  December  of  the  same  year.  After  this,  ex- 
periments were  carried  on  in  other  countries  and  many 
improvements  were  made. 

Why  a  balloon  rises.  The  principle  involved  in  the  rise 
of  the  balloon  is  similar  to  that  in  the  floating  of  a  boat. 
It  is  much  the  same  as  though  a  diver  in  the  water  should 
set  free  a  block  of  wood.  It  would  at  once  rise  to  the  surface 
because  it  is  lighter  than  water.  The  balloon  rises  till  it 
weighs  the  same  as  an  equal  volume  of  air  around  it,  the  air 
being  lighter  the  higher  up  one  goes.  The  balloon  con- 
tinues to  float  at  this  height  and  is  carried  by  the  wind  till 
some  of  the  gas  escapes,  and  then  the  balloon  gradually  falls 
to  the  ground.  When  the  balloonist  wishes  to  rise  higher,  he 
throws  out  sand  bags  which  have  been  placed  in  the  basket 
of  the  balloon ;  this  makes  it  lighter,  and  hence  it  rises.  If 
the  balloonist  wishes  to  descend,  he  pulls  a  line  that  opens  a 
valve  which  allows  the  gas  to  escape,  and  so  the  balloon 
sinks. 

DEMONSTRATION  23 

Purpose.     To  illustrate  the  principle  of  the  balloon. 

Apparatus.  Large-mouth  bottle,  rubber  stopper  with  two 
holes,  thistle  tube,  zinc,  hydrochloric  acid,  rubber  tubing. 

Directions.  Put  some  granulated  zinc  in  the  bottle.  Bend 
a  short  glass  tube  at  right  angles  and  push  one  end  in  one  of 


AIRSHIPS  AND   AIRPLANES  303 

the  holes  in  the  stopper.  Put  a  thistle  tube  through  the  other 
hole.  Put  the  stopper  in  the  bottle.  Push  down  the  thistle 
tube  nearly  to  the  bottom  of  the  bottle.  Add  water  till  it 
rises  to  cover  the  end  of  the  thistle  tube.  Push  one  end  of  a 
rubber  tubing  over  the  end  of  the  right  angle  tube.  Make  some 
soapsuds  in  warm  water.  Dip  the  end  of  the  rubber  tubing 
into  the  soapsuds.  .  Add  hydrochloric  acid  through  the  thistle 
tube.  Hydrogen  will  be  generated  and  will  pass  out  through 
the  tube  into  the  soapsuds.  Remove  the  tube  from  the  suds 
and  allow  a  bubble  to  form  on  the  end  of  the  tube.  Shake  it 
off.  Why  does  it  rise?  This  same  gas  is  often  used  to  fill 
balloons.  Apply  a  lighted  match  to  a  floating  bubble. 

Balloons  for  military  purposes.  Balloons  were  used  for 
military  purposes  during  the  Civil  War,  serving  as  a  van- 
tage point  from  which  the  enemy's  works  could  be  seen. 
Since  that  time  all  the  large  countries  have  made  some  use 
of  balloons  as  a  part  of  their  military  equipment. 

Dirigible  balloon.  The  next  great  step  in  the  develop- 
ment of  air  navigation  was  the  appearance  of  the  dirigible 

/Gas  bay 


Poinfs  of 
support 


Petrol 

Zxhaust 


FIG.  121.  —  Longitudinal  view  of  typical  dirigible  balloon. 

balloon,  or  airship.  This  was  propelled  by  artificial  means 
and  steered  by  a  rudder.  The  first  attempts  were  not  very 
successful  on  account  of  the  great  weight  of  the  engines 
used,  and  it  was  not  until  light  engines  of  great  horse  power 


304  SCIENCE  OF  HOME  AND   COMMUNITY 

were  developed  that  much  progress  was  made  in  air  navi- 
gation. 

The  first  successful  journey  in  a  dirigible  balloon  was 
made  in  France  in  1884.  Although  this  was  a  short  journey 
of  only  two  or  three  miles  and  return,  it  showed  the  possi- 
bilities that  there  are  in  this  kind  of  airship.  During  the 
last  fifteen  or  twenty  years  great  strides  have  been  made 
in  the  development  of  airships,  France  and  Germany  taking 
the  lead. 

Santos  Dumont.  Santos  Dumont  was  the  first  man  to 
attain  any  great  success  with  airships.  He  was  a  Brazilian 
by  birth,  but  he  carried  on  most  of  his  experiments  in 
France.  He  began  his  experiments  about  1898  and  his 
many  remarkable  successes  attracted  much  attention.  One 
of  the  chief  of  these  was  his  trip  around  the  Eiffel  Tower 
and  return  to  his  starting  place. 

Zeppelins.  Modern  airships  are  of  three  types,  —  rigid, 
non-rigid,  and  semi-rigid.  The  best  known  of  the  rigid  type 
are  those  of  Count  Zeppelin  of  Germany,  who  began  ex- 
perimenting with  airships  about  1898.  The  success  he  has 
attained  since  then  is  well  known  the  world  over.  He  began 
the  construction  of  airships  of  a  gigantic  size,  much  larger 
than  had  ever  before  been  attempted. 

The  framework  of  the  Zeppelin  is  made  of  aluminum,  and 
it  is  divided  into  separate  compartments,  each  of  which  con- 
tains a  gas  bag  filled  with  hydrogen  gas.  Suspended  from 
this  frame  are  two  boat-shaped  cars  between  which  is  a 
weight  running  on  a  rail,  by  which  the  balance  of  the  ship 
fore  and  aft  can  be  adjusted.  The  ship  is  driven  by  means 
of  four  propellers,  ten  feet  in  diameter,  each  with  three  blades. 
These  are  turned  by  two  powerful  engines  of  no  horse 
power,  one  in  each  car. 

At  the  rear  end  are  two  planes,  which  give  greater  sta- 
bility when  the  airship  is  traveling  rapidly.  Steering  up 
and  down  is  effected  by  means  of  elevating  planes,  and  steer- 


AIRSHIPS   AND   AIRPLANES 


305 


ing  to  the  right  and  left  is  controlled  by  a  triple  rudder  placed 
at  the  rear.  The  entire  ship  is  about  the  size  of  an  ocean 
steamer,  being  500  feet  long  and  about  50  feet  in  diameter. 
It  weighs  about  ten  tons  and  can  carry  six  tons  in  addition 
to  fuel,  cargo,  and  passengers.  It  can  travel  at  a  speed  of 
thirty  miles  an  hour.  Before  the  war  a  regular  passenger 
service  was  kept  up  in  Germany;  and  in  seven  months  183 
journeys  were  made,  carrying  all  together  nearly  4000  pas- 
sengers. These  airships  were  capable  of  carrying  twenty- 
four  persons  and  were  fitted  with  a  cabin  and  restaurant. 


FIG.  122.  —  A  Zeppelin  airship  over  Berlin. 

Later  forms  of  the  Zeppelins  have  three  cars  and  eight  en- 
gines, with  a  total  of  820  horse  power.  These  have  attained 
a  speed  of  75  miles  an  hour  and  can  stay  aloft  for  four  days 
and  nights. 

History  of  airplanes.  Leaving  the  subject  of  balloons 
and  airships,  we  now  come  to  a  study  of  airplanes,  machines 
that  are  heavier  than  air,  and  use  no  gas  to  hold  them  up. 
For  thousands  of  years  men  have  tried  to  devise  means  of 
flying.  The  first  crude  attempts  were  made  to  imitate  the 
shape  and  motion  of  a  bird's  wing. 

In  1886  Mr.  Wenhane  constructed  a  machine,  which 
contained  a  number  of  surfaces  arranged  in  tiers  one  above 


306  SCIENCE  OF  HOME  AND   COMMUNITY 

the  other ;  for  he  believed  that  a  single  surface  large  enough 
to  support  a  man  could  not  be  controlled  on  account  of  its 
great  size.  He  performed  some  interesting  experiments,  but 
he  was  not  able  to  accomplish  a  flight. 

About  twenty  years  later  Otto  Lilienthal,  in  Berlin,  carried 
on  experiments  in  gliding  or  soaring.  He  used  large  wings, 
and  starting  from  a  height  of  fifty  feet  or  less  he  would  glide 
with  the  wind.  In  one  of  these  flights  he  was  killed. 

Langley's  experiments.  Professor  Langley  of  Washington, 
D.  C.,  carried  on  some  successful  experiments  about  twenty 
years  ago  which  contributed  much  to  the  progress  of  flying 
machines.  He  built  a  small  model  of  a  flying  machine  not 
large  enough  to  carry  a  person.  It  was  provided  with  two 
sets  of  wings  about  twelve  feet  wide  and  the  whole  machine 
was  about  sixteen  feet  long.  It  was  driven  by  a  propeller 
turned  by  a  small  steam  engine.  It  was  steered  by  a  rudder 
which  worked  automatically.  After  several  years  of  ex- 
perimenting, the  machine  made  a  successful  flight  in  1896, 
remaining  in  the  air  for  a  minute  and  a  half.  This  was  the 
first 'flying  machine  ever  made  that  actually  propelled  itself 
through  the  air  driven  by  an  engine.  It  is  amazing  to  think 
of  the  progress  that  has  been  made  in  the  twenty  years  that 
have  elapsed  since  then. 

Wright  Brothers.  In  our  own  country  the  Wright  brothers 
carried  on  successful  experiments  in  gliding  during  1900  and 
the  years  following.  They  found  that  a  vertical  rudder  in 
the  rear  was  the  best  method  of  steering  to  the  left  and  right, 
and  that  a  horizontal  rudder  in  the  front  was  the  best  means 
of  guiding  the  machine  up  and  down.  In  1902  they  ac- 
complished a  glide  of  300  yards.  In  1903  they  attached  an 
engine  to  one  of  their  machines  and  made  their  first  successful 
flight.  Two  years  later  they  made  a  flight  of  24  miles  and 
landed  in  safety. 

In  1908  Wilbur  Wright  took  his  machine  to  France  and 
demonstrated  the  practical  value  of  the  airplane.  He  re- 


AIRSHIPS  AND   AIRPLANES 


3°7 


mained  in  the  air  more  than  two  hours,  and  carried  passen- 
gers at  a  height  of  400  feet.  From  this  time  on  very  rapid 
progress  was  made  in  the  development  of  the  airplane. 

Crossing  English  Channel.  A  prize  of  1000  pounds  was 
offered  by  an  English  newspaper  to  the  first  man  who  should 
cross  the  English  Channel  in  an  airplane.  Several  attempts 
were  made  to  win  this  prize.  The  first  attempt  was  made  by 
a  young  Frenchman,  M.  Hubert  Latham ;  but  he  was  un- 
successful, for  his  engine  stopped  after  he  had  started  across 
the  Channel,  and  he  was  obliged  to  descend  to  the  water  by 
a  series  of  long  glides.  His  machine  floated,  however,  and 


FIG.  123.  —  First  Wrigh£  plane. 

he  was  rescued.  The  next  attempt  was  made  by  another 
Frenchman,  Louis  Bleriot,  who  successfully  flew  across  the 
Channel  from  France  to  England  on  July  25,  1909,  and  thus 
won  the  prize. 

In  August  of  the  same  year  the  first  aviation  meet  was 
held  at  Rheims.  Here  many  wonderful  feats  were  per- 
formed in  a  great  variety  of  airships  and  airplanes.  A 
prize  was  offered  for  the  one  making  the  greatest  speed,  and 
another  for  the  one  attaining  the  greatest  height.  The  prize 
for  height  was  won  by  a  Frenchman,  M.  Latham,  who 
reached  a  height  of  500  feet.  The  prize  for  speed  was  won 
by  an  American,  Glenn  H.  Curtiss,  who  flew  at  the  rate  of 
47  miles  an  hour. 


308  SCIENCE  OF  HOME  AND   COMMUNITY 

Since  then  tremendous  progress  has  been  made  in  air 
navigation  in  the  distances  covered,  in  the  speeds 'attained, 
in  the  heights  reached,  and  in  the  number  of  passengers 
carried. 

Distances.  During  the  latter  part  of  1909,  Wilbur  Wright 
flew  with  a  passenger  for  an  hour  and  a  half.  Henry  Farnam 
remained  in  the  air  four  hours.  In  1910  Paulhan  flew  from 
London  to  Manchester,  a  distance  of  183  miles,  with  only 
one  stop,  and  won  the  prize  of  10,000  pounds  offered  by  the 
Daily  Mail  of  London.  In  America,  Curtiss  flew  from 
Albany  to  New  York,  a  distance  of  150  miles,  with  only  one 
stop.  In  1911  long  flights,  varying  from  800  to  1000  miles, 
were  made  in  various  parts  of  Europe.  During  the  latter 
part  of  1916  an  American  woman,  Ruth  Law,  made  a  con- 
tinuous flight  from  Chicago  to  Hornell,  New  York,  a  dis- 
tance of  590  miles.  The  entire  trip  from  Chicago  to  Gov- 
ernor's Island,  near  New  York  City,  a  distance  of  about 
900  miles,  was  made  in  a  little  less  than  nihe  hours  at 
an  average  speed  of  about  100  miles  an  hour.  In  1916 
Lieutenant  Marchal  made  a  non-stop  flight  of  812  miles 
from  France  to  Poland.  And  now  some  of  the  experts 
prophesy  that  a  trans-Atlantic  flight  will  be  made  in  the 
near  future. 

Speed.  There  has  also  been  a  wonderful  gain  in  the 
speed  attained.  In  1912  a  speed  of  72  miles  an  hour  was 
reached.  In  1916  in  America,  Mr.  Carlstrom  traveled  a 
distance  of  315  miles  at  the  rate  of  137  miles  an  hour,  or 
more  than  two  miles  a  minute.  From  47  miles  an  hour  to 
137  miles  is  the  progress  made  in  seven  years.  Army  air- 
planes are  reported  to  have  traveled  at  the  rate  of  more  than 
150  miles  an  hour.  In  January,  1918,  two  men  in  a  plane 
driven  by  liberty  motors  were  reported  in  the  newspapers  to 
have  traveled  from  Dayton  to  Cleveland,  Ohio,  a  distance 
of  215  miles,  in  i  hour  and  15  minutes.  This  is  at  the  rate 
of  172  miles  an  hour. 


AIRSHIPS  AND  AIRPLANES 


Other  lines  of  progress.  Each  year  sees  a  new  record 
established  in  the  height  attained  by  airplanes.  In  1919 
Captain  Schroeder  of  the  United  States  Army  Air  Service 
ascended  to  a  height  of  28,900  feet.  This  is  about  the  same 
as  the  height  of  Mt.  Everest,  the  highest  mountain  in  the 
world.  Still  more  recently  an  Englishman  is  reported  to 
have  reached  a  height  of  30,000  feet. 

Greater  weights  are  being  carried,  and  airplanes  are  now 
made  to  carry  a  number  of  passengers.  A  Curtis  seaplane 


FIG.  124.  —  English  military  biplane. 

recently  carried  50  passengers.  Some  airplanes  can  carry 
10,000  pounds  in  excess  of  their  own  weight. 

Progress  is  also  being  made  in  safeguarding  air  travel. 
The  serious  accident,  excepting  with  war  planes,  is  now 
the  exception.  The  Aero  Club  in  France  made  an  inves- 
tigation, which  showed  that  during  1912  only  one  fatal 
accident  occurred  for  every  92,000  miles  flown. 

Airplanes  in  war.  Even  before  the  great  European  War, 
the  leading  nations  had  spent  large  sums  of  money  on  air- 
planes, and  the'  airplane  branch  was  an  important  adjunct 


310  SCIENCE  OF  HOME  AND   COMMUNITY 

to  the  army.  During  this  war  airplanes  have  served  an 
important  purpose  as  scouts,  to  examine  the  enemies'  re- 
doubts, to  take  photographs,  to  detect  movements  of  soldiers, 
and  to  direct  the  artillery  fire. 

Several  distinct  types  of  airplanes  have  been  devised  for 
war  purposes,  such  as  the  scouting  plane,  the  fighting  plane, 
and  the  bombing  plane.  The  crew  of  a  scouting  plane  con- 
sists of  a  pilot  and  observer.  It  can  travel  at  great  speed 
afcd  was  used  to.  report  movements  of  the  enemy,  to  take 
photographs,  and  to  direct  artillery  fire  by  means  of  the 
wireless  outfit  with  which  it  is  provided.  The  fighting  plane 
carried  one  person  and  was  built  to  climb  quickly  and  fly 
faster  than  any  other  type  of  plane.  (See  figure  125.)  This 
was  equipped  with  a  machine  gun  which  could  be  fired 
straight  ahead,  between  the  propeller  blades,  without  hitting 
them.  The  bombing  planes  have  been  well  called  the  dread- 
naughts  of  the  air.  (See  figure  126.)  They  are  large  and 
powerful  and  so  constructed  that  they  can  carry  between 
one  and  two  tons  of  explosives.  These  were  used  to  drop 
bombs  on  vital  portions  of  the  enemies'  lines  such  as  supply 
depots  and  railway  junctions. 

During  this  war  such  tremendous  strides  have  been  made  in 
the  art  of  flying  there  seems  little  doubt  that  flying  machines 
and  airships  will  soon  be  common  throughout  the  civilized 
world,  and  will  be  used  for  commercial  purposes  to  transport 
passengers  and  cargoes.  Doubtless  more  rapid  develop- 
ment in  air  navigation  was  made  during  the  four  years  of 
war  than  would  have  been  made  in  fifteen  or  twenty  years  in 
peace  times. 

How  the  airplane  is  kept  up.  Having  traced  the  develop- 
ment of  the  airplane  from  its  crude  beginnings  to  its  present 
perfected  state,  we  may  next  inquire  how  it  is  constructed 
and  on  what  principle  it  works.  The  balloon  is  kept  up 
because  the  gas  which  it  contains  is  lighter  than  air;  but 
the  airplane  is  heavier  than  air  and  is  kept  up  by  a  different 


AIRSHIPS  AND  AIRPLANES  311 

principle.  It  is  very  much  like  the  principle  illustrated  in 
the  flying  of  a  kite.  In  the  first  attempts  that  were  made  to 
fly,  efforts  were  made  to  imitate  the  flapping  action  of  a 
bird's  wing;  but  to-day  airplanes  are  made  in  accordance 
with  the  principles  governing  the  soaring  bird  and  the  kite. 
If  a  person  holding  the  string  of  a  flying  kite  runs  against 
the  wind,  the  kite  rises.  There  are  three  forces  acting  on 
the  surface  of  the  kite :  the  wind,  the  string,  and  the  weight 
of  the  kite.  In  the  airplane,  the  pull  of  the  string  is  re- 
placed by  the  motion  of  the  propellers,  which  urge  the  air- 


FIG.  125.  —  French  fighting  airplane,  known  as  the  S.P.A.D. 

plane  onward  until  a  sufficient  wind  is  generated  to  lift  the 
airplane. 

Shape  of  planes.  Experiments  have  shown  that  the 
best  shape  for  a  plane  is  a  long,  narrow  surface,  with  the  long 
edge  at  right  angles  to  the  direction  of  flight.  Some  birds 
have  wings  that  are  fourteen  times  as  long  as  broad.  These 
planes  are  now  made  with  a  slightly  curved  surface,  as  it 
is  found  that  these  have  greater  lifting  power-  than  those 
with  flat  surfaces. 

Stability.  While  flying,  the  planes  encounter  many  cross 
currents  of  air,  which  tend  to  make  the  airplanes  unstable. 
In  order  to  give  the  plane  more  stability  in  a  longitudinal 
direction,  in  which  the  plane  is  traveling,  one  or  two  hori- 


312 


SCIENCE  OF  HOME  AND   COMMUNITY 


AIRSHIPS  AND   AIRPLANES  313 

zontal  planes  are  attached  to  the  rear.  To  give  stability 
in  a  lateral  direction,  several  devices  are  used.  In  the  Wright 
biplanes,  flaps  hang  down  from  the  main  planes,  which  can 
be  raised  or  lowered.  Another  method  often  found  on 
monoplanes  is  a  warping  of  the  tips  of  the  planes.  Ex- 
periments have  been  made  with  automatic  devices  to  keep 
the  plane  stable,  such  as  a  pendulum  or  gyroscope;  but  so 
far  with  little  success. 

Power.  Gasoline  engines  are  used  to  furnish  the  power 
to  propel  airplanes,  because  they  are  light  and  powerful. 
Engines  of  great  horse  power  are  being  used.  The  pro- 
pellers are  commonly  two  bladed  and  from  five  to  ten  feet 
in  diameter.  They  may  be  placed  either  in  front  or  behind. 
They  may  be  single  or  double. 

Starting  the  airplane.  In  order  that  an  airplane  shall 
glide  through  the  air,  it  must  have  an  initial  motion  given 
it  before  it  is  launched.  The  Wright  brothers  in  their  first 
experiments  started  their  machine  by  means  of  a  heavy  fall- 
ing weight,  which  drew  the  machine  along  a  track.  Modern 
machines  are  mounted  on  wheels,  and  the  motion  is  started 
by  the  propellers,  which  force  the  machine  over  the  ground. 
The  same  wheels  that  serve  for  starting  also  serve  for  alight- 
ing. Sometimes  these  are  provided  with  brakes,  and  some- 
times the  machine  has  skids,  on  which  it  alights  and  stops 
in  a  short  distance.  Hydroplanes  are  now  made  which 
can  start  from  the  water  and  alight  on  it.  The  wheels  are 
replaced  with  floats,  which  keep  the  machine  on  the  surface 
of  the  water. 

Running  the  airplane.  For  steering  there  must  be  two 
sets  of  rudders,  one  to  guide  the  plane  up  and  down,  and  one 
to  guide  it  to  the  right  and  left.  The  horizontal  plane*  used 
for  -the  first  purpose  may  be  placed  either  in  front  or  at  the 
rear.  The  vertical  plane  for  the  second  purpose  is  placed 
at  the  rear.  These  planes  are  both  controlled  by  levers 
within  easy  reach  of  the  aviator. 


314 


SCIENCE   OF  HOME  AND    COMMUNITY 


The  direction  of  flight  depends  on  the  speed  of  the  machine 
and  on  the  angle  that  the  planes  make  with  the  direction 
in  which  the  machine  is  being  driven.  An  increase  in  the 
angle  or  in  the  speed  tends  to  make  the  machine  rise,  a  de- 
crease to  make  it  fall,  so  that  by  the  proper  adjustment  of 
speed  and  angle  the  machine  may  be  made  to  go  in  a  hori- 
zontal plane.  As  the  direction  of  the  wind  is  constantly 
changing,  the  aviator  must  change  the  angle  of  the  planes 
to  correspond. 

Airplanes  easily  tip  from  side  to  side  on  account  of  the 
variation  in  air  currents  on  the  two  sides.  This  tendency 


FIG.  127.  —  Seaplane  scout,  a  submarine  chaser  of  the  air. 

to  tip  must  be  neutralized  in  some  way  by  the  aviator.  This 
is  most  frequently  done  by  warping  the  tips  of  the  planes,  or 
through  a  motion  of  small  flaps  attached  to  the  main  planes. 
These  are  controlled  by  means  of  a  lever,  which  connects 
with  the  tips  by  means  of  wires.  They  are  so  arranged  that 
as  the  tip  on  one  side  is  warped  up,  the  tip  on  the  other  side 
is  warped  down.  They  can  be  so  manipulated  as  to  check 
the  tendency  of  the  machine  to  rock  from  side  to  side. 

In  making  a  turn,  the  part  of  the  machine  on  the  outside 
of  the  curve  travels  faster  than  the  part  on  the  inner  side 
and  so  tends  to  rise.  This  tendency  is  controlled  by  warping 
the  tips  of  the  planes  just  as  in  keeping  the  machine  balanced 
in  ordinary  flight.  In  the  first  planes  the  aviator  was  ex- 


AIRSHIPS  AND   AIRPLANES  315 

posed  to  the  weather,  but  in  the  later  ones  inclosed  cabins 
are  made. 

Types  of  airplanes.  Two  types  of  airplanes  are  being 
commonly  used,  the  monoplane  and  the  biplane.  And  in 
recent  years  triplanes  are  being  made.  The  monoplane  has 
one  large  plane  on  each  side ;  while  the  biplane  has  two 
planes  on  each  side,  one  above  the  other.  Biplanes  are 
slower  than  monoplanes,  but  they  can  carry  heavier  loads. 
A  brief  description  will  be  given  of  one  of  each  of  the  first 
two  types. 

Bleriot  monoplane.  The  Bleriot  monoplane,  which  is  made 
to  carry  two  passengers,  is  27^-  feet  long  and  has  a  span  from 

Too  st&ying  wires 
Wires  f/x/ng  front  edge  of  \ 


edge  of  wing- 

^:£pr^^^^a-FTiii     x^^/iE^—  lyAV^y*^ 

E/evator-~~        ~^c-    j       /    / /r itey      i  j — -^\x  \\\  ///s^&i   n        ^-r*  \w     ^Friejtne 


Warping  wires'  ^Land/ng  whee/s 

FIG.  128.  —  Bleriot  monoplane. 

tip  to  tip  of  36  feet.  The  area  of  the  main  plane  is  263  square 
feet.  The  whole  machine  weighs  700  pounds,  and  it  is  driven 
by  a  gasoline  engine  of  50  horse  power.  One  lever,  moved 
by  hand,  controls  the  warping  of  the  wings  when  moved  in 
one  direction,  and  governs  the  lifting  tail  when  moved  in 
another.  The  rudder  is  controlled  by  a  foot  pedal. 

Wright  biplane.  The  Wright  biplane  has  two  canvas- 
covered  wings  arranged  one  above  the  other  about  6  feet 
apart.  Each  wing  is  40  feet  wide  and  6J  feet  long.  The 
total  area  of  these  wings  is  500  square  feet.  In  the  first 
machines  there  were  placed  in  front  two  smaller  horizontal 
planes,  with  an  area  of  about  60  square  feet,  which  could  be. 


316  SCIENCE  OF  HOME  AND   COMMUNITY 

warped  so  as  to  steer  the  machine  up  and  down.  In  the 
later  machines  these  planes  are  mounted  in  the  rear.  At 
the  rear  also  there  are  two  vertical  rudders  for  steering  the 
machine  to  the  right  and  left.  The  balance  is  maintained 
by  warping  the  rear  corners  of  the  wings,  which  are  made 
movable.  A  single  lever  controls  both  the  warping  of  the 
wings  and  the  action  of  the  two  vertical  rudders. 
jj.  On  the  frame  between  the  two  main  wings  are  carried  the 
engine  and  the  seats  for  the  operator  and  passenger.  The 
machine  weighs  900  pounds  and  is  driven  by  a  25  horse 
power  gasoline  engine,  which  turns  two  twin-bladed  pro- 
pellers in  opposite  directions  at  the  rate  of  400  revolutions 
a  minute.  If  anything  should  happen  to  stop  the  engine 
while  in  the  air,  the  machine  can  glide  to  the  ground  and 
land  safely.  The  later  machines  are  provided  with  wheels 
for  starting  and  'alighting. 

Comparison  of  airship  and  airplane.  In  comparing  the 
airship  and  airplane,  we  find  that  each  has  its  advantages. 
The  airship  is  safer,  can  carry  a  much  greater  weight,  and 
can  stay  in  the  air  longer.  On  the  other  hand,  the  airplane 
can  travel  faster  and  is  much  smaller  and  cheaper  to 
make.  We  might  perhaps  compare  the  airship  with  the 
freight  train  that  carries  heavy  loads  and  the  airplane  with 
the  express  train  that  carries  lighter  loads  and  travels 
faster. 

There  seems  little  question  that  within  a  short  time 
regular  passenger  routes  by  means  of  airships  and  airplanes 
will  be  established  in  this  country,  and  that  we  may  soon 
have  the  novel  sensation  of  traveling  through  the  air  faster 
than  the  express  train  travels.  And  all  the  time  we  shall 
be  enjoying  a  magnificent  view  of  the  country  over  which 
we  are  passing. 

Shortly  after  the  signing  of  the  armistice  in  November, 
1918,  there  was  established  an  air  passenger  service  between 
London  and  Paris.  The  journey  takes  only  2-J-  hours.  Dur- 


AIRSHIPS  AND  AIRPLANES  317 

ing  two  months   1200  passengers  were  carried  across  the 
Channel. 

SUPPLEMENTARY  QUESTIONS  FOR  CLASS  DISCUSSION 

1.  Which  seems  to  have  greater  possibilities  for  the  future, 
the  airship  or  the  airplane  ? 

2.  How  does  the  airman  control  his  airplane? 

3.  How  are  airplanes  kept  from  tipping? 

REFERENCES 

Cressey,   Discoveries  and   Inventions  of  the    Twentieth   Century, 

E.  P.  Button  Co.,  New  York  City.     Chap.  16. 
Darrow,  The  Boys'  Own  Book  of  Great  Inventions,  Macmillan  Co., 

New  York  City.     Chaps.  8-9. 
Delacombe,  Boys'  Book  of  Airships,  F.  A.  Stokes  Co.,  New  York 

City. 
Johnson,   Modern  Inventions,  F.  A.  Stokes  Co.,  New  York  City. 

Chaps.  3,  4,  6,  7. 
Maule,   Boys'   Book  of    New  Inventions,  Grosset  and    Dunlap, 

New  York  City.     Chaps.  1-3. 
Navigating  the  Air,  by  the  Aero  Club,  Doubleday  Page  and  Co., 

New  York  City. 


SECTION  B 
MEANS  OF  COMMUNICATION 

CHAPTER  XXI 
THE  TELEGRAPH 

1 .  What  are  the  essential  parts  of  a  telegraph  sys- 
tem ?  how  do  they  work  ? 

2.  How  does  the  wireless  telegraph  differ  from  the 
ordinary  telegraph  ? 

Use  of  the  telegraph  in  daily  life.  There  are  many  won- 
derful machines,  very  important  in  our  daily  lives,  to  which 
we  have  become  so  accustomed  that  we  hardly  realize  what 
they  do  for  us.  This  is  true  of  the  telegraph.  Let  us  stop 
for  a  moment  to  see  how  much  we  owe  to  this  wonderful 
little  instrument.  We  are  apt  to  think  of  the  telegraph  only 
in  connection  with  bringing  the  sad  news  of  the  death  or 
sickness  of  a  friend  or  relative.  But  this  is  only  an  occasional 
use.  We  receive  the  benefit  of  the  telegraph  every  day  of 
Our  lives,  many  times  unconsciously. 

Newspapers.  Each  day  the  newspaper  brings  to  our 
doors  news  which  has  been  flashed  from  every  part  of  the 
world  by  the  telegraph.  We  were  able  to  follow  the  hap- 
penings of  the  great  war  in  Europe  from  day  to  day,  and  to 
receive  the  news  of  a  battle  only  a  few  hours  after  it  was 
fought.  When  President  Wilson  makes  a  speech  in  any 
part  of  the  United  States  or  Europe,  the  next  day's  papers" 
give  the  entire  speech  to  all  parts  of  the  country.  As  one 

318 


THE  TELEGRAPH  319 

looks  over  the  items  of  a  daily  newspaper,  it  will  be  found  that 
the  great  majority  of  items  have  been  sent  in  by  telegraph. 

Elections.  On  election  day  citizens  in  all  parts  of  the 
country  cast  their  ballots.  By  midnight  of  the  same  day 
returns  are  telegraphed  into  headquarters,  and  even  in 
presidential  elections  by  the  next  morning  the  whole  country 
usually  knows  who  has  been  elected  president. 

Baseball.  During  the  World  Series  of  baseball  games  be- 
tween Boston  and  Brooklyn  in  1916,  thousands  of  baseball 
fans  were  gathered  together  in  all  the  large  cities  near  the 
telegraph  offices,  and  were  able  to  watch  the  returns  inning 
by  inning  as  they  were  brought  in  by  the  telegraph,  and 
only  a  few  minutes  after  the  fourth  game  was  finished,  these 
thousands  of  people  knew  that  Boston  had  again  won  the 
world's  championship. 

Weather  forecast.  Each  day's  paper  contains  the  weather 
forecast  of  the  next  day's  weather.  This  is  made  possible 
because  reports  of  weather  conditions  in  two  hundred  locali- 
ties are  telegraphed  to  Washington  and  other  cities,  where 
forecasts  of  weather  are  made  as  a  result  of  these  reports. 

Railroads.  The  telegraph  is  indispensable  in  the  running 
of  railroad  trains.  As  explained  in  Chapter  XVI,  when- 
ever a  train  arrives  at  a  station,  the  news  is  telegraphed  to 
a  man  called  a  dispatcher  located  at  headquarters,  who 
arranges  the  places  where  the  trains  shall  meet  and  pass, 
thus  avoiding  accidents. 

Clocks  run  by  telegraph.  Clocks  may  now  be  regulated  by 
electricity.  A  certain  accurate  clock  is  taken  as  the  stand- 
ard ;  other  clocks,  connected  with  this,  have  a  mechanism  so 
that  the  minute  hand  is  set  forward  or  back,  as  may  be  neces- 
sary to  keep  the  clock  in  unison  with  the  standard  clock. 

Other  uses.  The  telegraph  is  of  great  value  to  the  business 
man  in  his  ordinary  business  transactions.  If  he  wishes 
to  order  some  material  which  he  needs  at  once,  he  can  send 
a  telegram  and  secure  the  order  on  the  next  train.  If  a 


320  SCIENCE  OF  HOME  AND   COMMUNITY 

great  flood  or  fire  devastates  a  city  and  leaves  the  people 
destitute  and  homeless,  the  telegraph  sends  out  the  news 
and  relief  comes  back  at  once. 

Compare  the  conditions  to-day  with  those  a  hundred  years 
ago*  when  there  were  no  railroads  nor  telegraphs.  The 
battle  of  New  Orleans,  in  the  War  of  1812,  was  fought  after 
the  treaty  of  peace  had  been  signed,  because  the  news 
traveled  so  slowly  that  the  soldiers  had  not  yet  learned  that 
the  war  was  ended. 

History  of  the  telegraph.  On  May  24,  1844,  the  now 
famous  words,  "  What  hath  God  wrought,"  were  sent  by 

telegraph  from  Washing- 
ton to  Baltimore,  a  dis- 
tance of  forty  miles.  The 
credit  for  this  achievement 
of  being  the  first  to  send 
messages  at  this  distance 
belongs  to  Samuel  Morse. 
Back  of  this  success, 
however,  is  a  story  of 
struggle,  poverty,  and  per- 
sistence. Samuel  Morse 
was  a  professor  in  the 
University  of  the  City  of 
New  York,  and  he  gave 
his  spare  time  to  a  study 
of  electricity.  In  1832 
he  conceived  the  idea  of 
conveying  signals  at  a 

FIG.  1 29.  —  Morse  and  his  first  instrument. 

distance     by    means     of 

electricity.  He  worked  for  eleven  years  in  perfecting  his 
instrument,  which  was  finally  finished  in  1843.  He  then 
devised  a  system  of  dots  and  dashes  for  sending  messages. 
During  this  period  he  underwent  many  deprivations  in 
order  to  get  enough  money  to  carry  on  his  experiments. 


THE  TELEGRAPH  321 

Before  this,  many  experiments  had  been  tried  in  sending 
messages  by  electricity ;  some  had  'been  partially  successful, 
but  none  of  them  had  suggested  any  possibility  of  com- 
mercial success.  Morse's  success  was  made  possible  only 
through  the  inventions  of  other  men,  whose  results  he  put 
together  in  the  construction  of  the  telegraph.  Two  of  the 
most  important  of  these  were  the  invention  of  the  electric 
magnet  and  of  a  constant  battery  to  furnish  electricity.  i 

He  made  application  to  Congress  fo^  aid  to  build  a  tele- 
graphic line  between  Washington  and  Baltimore.  He  was 
finally  successful  in  his  appeal  and  in  1843  received  an  ap- 
propriation of  $30,000.  With  this,  a  line  between  the  two 
cities  was  constructed  and  the  first  message  was  sent. 

This  first  line  proved  so  successful  that  the  telegraph  was 
soon  in  use  in  all  parts  of  the  world.  By  1861  a  line  had 
been  built  connecting  New  York  with  San  Francisco. 

To-day  there  is  a  network  of  telegraph  lines  extending 
over  the  whole  country.  In  1914  there  were  240,000  miles 
of  line  (equal  to  the  distance  to  the  moon)  and  1,600,000 
miles  of  wire.  In  1912  it  was  estimated  that  there  were 
90,000,000  messages  sent  out,  or  nearly  one  for  every  person 
in  the  United  States. 

Atlantic  cable.  The  next  great  step  was  the  laying  of  the 
Atlantic  cable  in  1857  from  Newfoundland  to  Ireland,  so 
that  messages  could  be  sent  across  the  ocean.  The  credit 
for  this  is  due  largely  to  Cyrus  W.  Field.  After  the  cable  had 
been  used  successfully  for  eighteen  days,  however,  it  ceased 
to  work.  At  the  close  of  the  Civil  War,  Mr.  Field  deter- 
mined to  lay  another  cable.  He  started  out  in  1865  with 
2300  miles  of  cable  on  board  the  Great  Eastern,  at  that  time 
the  largest  vessel  in  the  world.  About  a  thousand  miles  from 
starting,  the  cable  parted  and  they  were  unable  to  find  it. 
In  the  following  year,  1866,  another  attempt  was  made, 
which  proved  successful.  From  that  time  there  has  been 
telegraphic  communication  between  America  and  Europe. 


322 


SCIENCE  OF  HOME  AND   COMMUNITY 


ADJUSTING  SCREWS 
CONTACT- 


BUTTON 


FIG.  130.  —  Telegraph  key. 


How  the  telegraph  works.  Some  improvements  have 
been  made  in  the  telegraph  since  Morse's  day,  but  in  prin- 
ciple the  telegraph  in  use  to-day  is  the  same  as  that  invented 
by  Morse.  The  telegraph  consists  of  four  parts,  the  sender, 
or  key,  the  sounder,  the  relay,  and  the  batteries.  Figure  132 

shows    how    these    various 
parts  are  arranged. 

The  key.  The  structure 
of  the  sender,  or  key,  is 
shown  in  figure  130.  This 
consists  of  a  lever  with  a 
button  at  one  end.  On  the 
under  side  is  a  point  which 
makes  contact  with  another 
point  directly  beneath  it.  These  two  points  are  ordinarily 
separated  by  a  spring.  When  the  key  is  not  being  used,  the 
switch  is  shut  so  that  the  circuit  is  closed.  When  the  key 
is  to  Be  used,  the  switch  is  opened.  When  the  button  is 
pushed  down,  the  two  points  come  in  contact  and  the  current 
passes  through,  thus  affecting 
the  relay  and  the  sounder  at 
the  other  end. 

Sounder.  The  sounder  is 
shown  in  figure  131.  This 
consists  of  two  electromag- 
nets, and  over  these  a  bar, 
pivoted  at  one  end.  Just 
over  the  electromagnets  is 
the  armature.  Ordinarily  the  bar  is  kept  back  by  a  spring  so 
that  the  armature  does  not  touch  the  electromagnet.  The 
distance  that  the  bar  can  be  pulled  down  is  controlled  by  a 
screw.  When  the  key  of  the  sender  is  closed,  the  current 
passes  through  the  coils  of  wire  and  the  electromagnet  be- 
comes magnetized,  thus  pulling  down  the  armature.  When 
the  key  is  open  the  current  ceases  to  flow  through  the  coils  so 


FIG.  131.  —  Telegraph  sounder. 


THE  TELEGRAPH  323 

that  these  are  no  longer  a  magnet,  and  hence  the  armature  is 
pulled  back  by  the  spring.     Thus  two  sounds  are  made,  one 
when  the  armature  is  drawn  down,  and  another  when  it  is 
'released  by  the  striking  of  the  bar  against  the  screw. 

Morse  alphabet.  When  these  two  sounds  come  very  close 
together,  so  that  they  seem  as  one,  the  signal  is  called  a  dot. 
Where  they  are  separated  by  an  appreciable  time,  so  that 
two  distinct  sounds  are  heard,  the  signal  is  called  a  dash. 
The  different  letters  are  represented  by  various  combina- 
tions of  dots  and  dashes.  The  American  code  of  the  Morse 

alphabet  is  as  follows:  A  •--  B C  •  •  •    D E  • 

p. —    G-    —    H-...    !••     J K L- 

M-      -  N—   O  •  .   R Q R.  ••    S  ...    T- 

U V W  —     -  X Y  •  •••    Z  •.•. 

These  dots  and  dashes  may  be  recorded  on  a  strip  of  paper 
run  by  clockwork,  which  passes  under  a  point  attached  to 
the  sounder.  When  the  key  is  held  down  for  a  dash,  a 
longer  mark  is  made  on  the  paper  than  when  the  key  is  held 
down  for  a  dot.  The  telegraph  operator  can  learn  by 
practice  to  read  the  signals  by  ear  and  write  them  down 
directly  as  fast  as  they  come  in.  This  method  is  commonly 
used. 

If  the  two  stations  are  only  a  short  distance  apart,  the 
sender,  sounder,  and  batteries  are  all  that  are  necessary  for 
sending  messages.  But  when  the  stations  are  long  distances 
apart,  the  wire  offers  so  much  resistance  that  the  sounder  is 
worked  only  very  weakly  or  not  at  all,  so  that  no  signals  are 
transmitted. 

Relay.  To  overcome  this  difficulty,  a  relay  is  used.  The 
method  of  connecting  this  is  shown  in  figure  132.  There  are 
two  distinct  circuits,  first,  the  long  distance  circuit  which 
operates  the  relay,  and  second,  the  local  circuit  which 
operates  the  sounder.  In  the  long  distance  circuit  only 
one  wire  is  needed  as  the  ground  serves  as  another  conductor 
through  which  the  current  returns.  The  ends  of  the  main 


324 


SCIENCE  OF  HOME  AND  COMMUNITY 


Rounder 


Earth 


FIG.  132.  —  Diagram  of  relay 
telegraph  circuit. 


line  are  attached  to  pieces  of  metal  sunk  in  the  ground  so 
as  to  make  good  connections. 

The  relay  (figures  132  and  133)  is  somewhat  like  the 
sounder.  It  consists  of  an  electromagnet  and  an  armature. 
When  a  current  passes  through  the 
magnet,  the  armature  is  drawn  down 
and  contact  between  two  points  is 
made.  This  closes  the  local  circuit, 
and  the  local  battery  is  brought  into 
play,  which  operates  the  sounder.  By 
means  of  these  relays,  telegrams  may 
be  sent  long  distances,  even  across 
the  continent.  The  message  may  be 
sent  to  one  city,  as  from  New  York 
to  Chicago,  and  then  the  message  can 
be  repeated  at  Chicago  and  sent  to 
San  Francisco. 

Duplex  telegraphy.  When  the  telegraph  was  first  used, 
only  one  message  could  be  sent  at  a  time  over  the  wire ;  but 
in  a  few  years  the  system  of  duplex  telegraphy  was  invented 
by  means  of  which  two  messages  could  be  sent  at  the  same 
time  in  opposite  directions. 
Then,  later,  diplex  telegraphy 
made  it  possible  to  send  two 
messages  in  the  same  direc- 
tion at  the  same  time  on  one 
wire.  The  next  development 
allowed  two  messages  to  be 
sent  from  each  end  of  the  line 
at  the  same  time,  or  four  in  all.  Now  we  have  the  multiplex 
telegraphy  by  means  of  which  many  messages  can  be  sent  in 
both  directions  at  the  same  time.  It  has  been  found  possible 
to  send  thirty-six  messages  in  each  direction  at  the  same 
time.  In  actual  practice,  however,  it  has  been  found  best 
to  limit  this  to  six  in  each  direction.  For  this  work  twelve 


FIG.  133.  —  Telegraph  relay. 


THE  TELEGRAPH  325 

operators  are  needed  at  each  end,  six  to  send  and  six  to  re- 
ceive; one  line  may  thus  employ  twenty-four  operators. 
For  this  there  must  be  a  separate  key  for  each  sender  and  a 
separate  sounder  for  each  receiver. 

High  speed  telegraphy.  When  it  is  desired  to  transmit 
long  messages  for  newspapers,  the  hand  method  of  sending 
would  be  too  slow.  For  this  purpose  machines  are  used 
which  send  messages  with  great  rapidity.  Several  systems 
are  able  to  send  400  words  per  minute.  In  one  system  words 
have  been  sent  at  rates  varying  from  1000  to  3000  words  per 
minute.  This  is  much  more  rapid  than  even  the  telephone. 

The  words  of  the  message  are  first  translated  into  the 
Morse  alphabet,  and  perforations  are  made  by  a  machine 
on  a  strip  of  paper  to  correspond  to  the  dots  and  dashes  of 
the  alphabet.  This  is  done  by  a  machine  much  like  a  type- 
writer, each  key  of  which  makes  the  holes  that  correspond 
to  the  dots  and  dashes  for  that  letter.  This  strip  of  paper 
is  run  through  telegraphic  instruments  so  arranged  that  the 
signals  are  transmitted  to  the  other  end. 

Various  means  are  used  to  receive  these  messages.  One 
of  the  most  common  is  an  electrochemical  receiver.  Paper 
is  covered  with  certain  chemicals  which  are  decomposed  by 
the  electric  current  and  leave  markings  on  the  paper.  One 
combination  used  is  starch  and  potassium  iodid.  When 
this  salt  is  decomposed,  the  iodin  is  set  free,  and  when  it 
comes  in  contact  with  the  starch  it  produces  a  blue  color. 
Machines  are  now  in  use  which  reproduce  the  message  in 
typewritten  form,  ready  for  instant  delivery  and  use. 
This  machine  has  made  a  record  of  100  words  a  minute. 

Facsimile  telegraphy.  Devices  are  now  used  which  make 
it  possible  to  transmit  accurate  copies  of  charts,  diagrams, 
pictures,  and  signatures  over  a  telegraph  line.  This  is  called 
facsimile  telegraphy.  If  a  person  takes  a  pen  in  a  telegraph 
office  and  writes  a  message,  it  is  possible  to  reproduce  it  so 
accurately  at  the  other  end,  that  the  handwriting  may  be 


326  SCIENCE  OF  HOME  AND   COMMUNITY 

recognized.  Thus  it  is  possible  for  a  person  to  telegraph 
his  signature  to  a  check  or  other  paper  requiring  a  personal 
signature.  This  is  called  the  writing  telegraph  or  telauto- 
graph. 

By  means  of  the  printing  telegraph,  messages  may  be  sent 
so  that  they  are  received  printed  on  a  strip  of  paper.  The 
stock  ticker,  which  is  one  form  of  this,  is  very  widely  used 
among  brokers. 

DEMONSTRATION  24 

Purpose.     To  show  how  a  set  of  telegraph  instruments  work. 

Apparatus.     Sounder,  sender,  relay,  cells.  - 

Directions.  Connect  the  parts  of  the  telegraph  instruments 
including  the  relay,  as  shown  in  figure  132.  Study  each  part 
carefully  to  see  how  it  works.  Make  a  drawing  showing  the 
connections.  Try  sending  some  of  the  letters  of  the  Morse 
alphabet. 

Wireless  telegraphy.  Use.  If  to-day  a  ship  at  sea  is  in 
danger  of  sinking  on  account  of  some  accident,  the  operator 
of  the  wireless  telegraph  sends  out  the  S.  O.  S.  signal,  the 
call  for  help.  This  travels  in  every  direction  for  many  miles, 
and  some  ship  is  almost  certain  to  receive  the  message  and 
will  hasten  then  to  the  aid  of  the  crippled  ship.  Thus  many 
lives  have  been,  saved,  and  the  sea  is  now  robbed  of  many  of 
its  terrors  by  the  wireless  telegraph. 

Nearly  all  the  ocean  liners  are  provided  with  wireless 
telegraph  instruments,  so  that  people  on  board  can  keep  in 
communication  with  their  friends  on  shore,  and  the  business 
man  can  still  direct  his  affairs.  Daily  newspapers  are  pub- 
lished on  some  of  the  larger  boats,  the  news  having  been 
received  by  wireless. 

History  of  wireless  telegraph.  The  chief  credit  for  the 
development  of  wireless  telegraphy  is  due  to  Marconi,  who 
was  the  first  to  develop  a  practical  instrument.  As  is  true 
of  all  inventions,  this  was  made  possible  only  through  the 


THE  TELEGRAPH  327 

work  of  many  men  before  him,  who  had  made  discoveries 
which  he  used  in  constructing  his  instruments.  While  still 
but  a  young  man  of  2 1  years,  he  transmitted  signals  without 
wires  through  a  distance  of  two  miles.  This  was  in  1896. 
In  1897  this  distance  was  increased  to  18  miles,  and  in  1899 
messages  were  sent  across  the  English  Channel,  a  distance 
of  32  miles.  He  next  directed  his  attention  to  telegraphing 
across  the  Atlantic  Ocean;  and  in  1901,  a  signal  was  sent 
from  England  to  Newfoundland,  a  distance  of  1800  miles. 
These  and  other  stations  have  been  improved  until  now  a 
number  of  companies  are  doing  business  in  sending  messages 
across  the  ocean.  Messages  are  now  sent  more  than  4000 
miles. 

Waves.  If  a  stone  is  thrown  into  a  pond,  water  waves  are 
sent  out  and  spread  in  every  direction.  In  a  similar  manner 
light  and  electricity  travel  by  wave  motion.  Scientists 
believe  that  all  space  is  filled  with  a  very  thin  substance 
which  they  call  ether.  (This  has  nothing  to  do  with  the 
ether  used  in  medicine.)  It  is  really  no  more  wonderful 
that  electricity  should  travel  through  this  ether  without 
wires  than  that  light  should  come  to  us  from  the  sun.  It 
seems  more  strange  because  the  light  waves  affect  our  eyes, 
and  we  are  able  to  see  objects  by  means  of  the  light  waves 
that  come  from  them.  Electricity  travels  by  means  of  waves 
which  we  cannot  detect  through  our  senses  as  we  can  light 
waves;  but  instruments  have  been  made  which  detect 
these  waves. 

Sender.  A  wireless  outfit  consists  of  a  sending  apparatus 
to  send  out  electric  waves,  and  a  receiving  apparatus  to 
receive  these  waves  sent  out  from  another  station.  The 
connections  of  these  parts  are  shown  in  figure  134.  The 
sending  apparatus  consists  of  some  source  of  current  elec- 
tricity such  as  batteries  B,  an  induction  coil  I,  Leyden  jars,  a 
spark  gap ,  and  a  key  K,  to  control  the  current .  The  induction 
coil  is  an  instrument  by  means  of  which  an  electric  current 


328 


SCIENCE  OF  HOME  AND   COMMUNITY 


of  low  voltage  may  be  changed  to  one  of  high  voltage.     The 
Leyden  jars  serve  to  store  up  electricity  till  a  heavy  charge  has 

accumulated.  When 
sufficient  electricity 
has  been  stored  in 
the  jars,  it  jumps 
across  the  spark  gap 
with  tremendous 
force,  and  this  starts 
the  electric  waves, 
which  are  transmit- 
ted in  every  direc- 
tion. In  order  to 
make  these  waves 
carry  through  long 
distances ,  long  wires 
called  antennae  are 
connected  with  the 
sending  apparatus. 
In  some  stations 
wires  200  feet  high 
are  used.  The 
waves  thus  sent  out 
follow  the  curva- 
ture of  the  earth,  so 
that  the  effect  may 
be  felt  by  instru- 
ments several  thou- 
sand miles  away. 
Receiving  apparatus.  The  most  important  part  of  the 
receiving  apparatus  is  the  detector,  or  coherer,  as  it  is  called. 
The  purpose  of  this  instrument  is  to  detect  the  presence  of 
the  electric  waves.  Many  different  kinds  have  been  de- 
vised. One  that  has  been  much  used  by  Marconi  consists 
of  a  small  glass  tube,  plugged  at  each  end,  and  having  the 


-^r  Earth 

FIG.  134.  —  Wireless  sending  apparatus. 


THE  TELEGRAPH 


329 


intervening  space  filled  with  metal  filings.  Under  ordinary 
conditions  these  filings  do  not  conduct  electricity,  but  when 
they  are  acted  upon  by  an  electric  wave,  they  change  their 
positions  and  arrange  themselves  in  such  a  way  that  an 
electric  current  can  pass  through  them.  The  connections 
for  a  receiving  instrument  are  shown  in  figure  136.  When 
the  filings  become  affected  by  the  electric  waves,  the  current 
from  the  battery  B  passes  through  and  this  operates  a  relay 
M.  When  this  relay  is  closed,  a  second  circuit  is  brought 


FIG.  135.  —  Wireless  telegraph  station  at  Glace"  Bay. 

into  action,  including  the  battery  b,  the  tapper  and  the 
telegraph  sounder.  This  tapper  is  called  the  decoherer  be- 
cause, when  it  strikes  the  coherer,  it  breaks  up  the  regular 
arrangement  of  filings  so  that  they  cease  to  conduct  elec- 
tricity. The  tapper  works  like  an  electric  bell.  In  this 
same  circuit  is  placed  the  recording  instrument,  which  is 
similar  to  a  regular  telegraph  sounder.  In  order  that  the 
sounds  may  be  more  easily  heard,  listening  attachments  are 
placed  over  the  ear. 

The  Morse  code  of  telegraph  signals  is  used.     In  this  case, 
however,  the  dash  becomes  a  series  of  rapid  dots  very  close 


330 


SCIENCE  OF  HOME  AND   COMMUNITY 


together,  because  the 
action  of  the  decoherer 
does  not  allow  a  dash 
to  be  made. 

Tuning.  After  it 
had  been  found  pos- 
sible to  send  messages 
by  wireless  over  long 
distances,  one  of  the 
first  difficulties  that 
arose  was  how  to  do 
this  in  such  a  way 
that  other  instruments 
than  the  one  for  which 
it  was  intended  should 
not  receive  the  mes- 
sage. Many  experi- 
ments have  been  tried 
and  now  this  privacy 
is  insured  by  a  system 
of  tuning,  as  it  is 
called.  This  is  done  by 
regulating  the  wave 
length  that  is  given 
out  by  a  certain  send- 
ing apparatus,  so  that 
it  can  be  received  only 
by  an  apparatus  which 
is  tuned  to  correspond 
to  the  same  wave 
length.  But  in  order 
—  Earth  £Q  msure  secrecy,  codes 

F,o.  136.  -  Wireless  receiving  apparatus.  ^  ^  ^^  ^  b& 

understood  only  by  those  who  know  the  key  to  the  code.     A 
single  word  may  stand  for  a  whole  sentence. 


THE  TELEGRAPH  331 

DEMONSTRATION  25 

Purpose.     To  show  how  the  wireless  telegraph  works. 

Apparatus.     A  small  demonstration  fojm  of  wireless  outfit. 

Directions.  Set  up  the  outfit  following  the  directions  that 
accompany  it.  Study  carefully  the  working  of  the  various 
parts.  Make  a  drawing  showing  the  parts  and  their  connec- 
tions. See  how  far  apart  the  sender  and  receiver  can  be  placed 
and  still  send  and  receive  messages. 

Comparison  of  wireless  and  ordinary  telegraph.  When 
we  come  to  compare  the  wireless  and  ordinary  telegraph, 
the  first  thing  we  note  is  the  fact  that  wireless  is  much 
cheaper  to  construct,  because  no  connecting  wires  are  neces- 
sary. This  is  especially  evident  when  we  consider  how  much 
it  cost  to  lay  the  Atlantic  cable  in  order  that  we  might 
telegraph  across  the  ocean.  And  on  land  after  the  lines  of 
wires  are  set  up  there  is  the  expense  of  maintaining  the  poles 
and  wires,  which  are  often  broken  down  by  storms,  and  of 
replacing  the  poles  as  they  decay. 

For  communication  on  water  between  boats  or  between 
boats  and  land,  of  course,  only  the  wireless,  can  be  used.  In 
certain  mountainous  countries,  or  in  countries  where  heavy 
snowstorms  are  common  as  in  Alaska,  the  wireless  is  much 
easier  to  install  and  operate.  For  regular  service  between 
points  where  the  telegraph  is  already  established,  this  is 
largely  used  in  preference  to  the  wireless.  Whether  the 
wireless  will  ever  be  a  serious  competitor  for  this  trade  it 
is  difficult  to  say.  But  for  long  distance  telegraphy  over  the 
ocean,  there  are  a  number  of  commercial  stations  of  wireless 
running  in  competition  with  the  cable  service. 

SUPPLEMENTARY  QUESTIONS  FOR  CLASS  DISCUSSION 

1.  What  part  does  the  telegraph  play  in  our  daily  life? 

2.  What  has  been  the  history  of  the  development  of  the 
telegraph  ? 


332  SCIENCE  OF  HOME  AND   COMMUNITY 

3.  How  can  the  parts  of  a  telegraph  system  be  used  to  send  a 
message  ? 

4.  How  are  messages  sent  at  high  speed? 

5.  What  advantages  have  the  wireless  and  ordinary  telegraph 
each  over  the  other  ? 

REFERENCES 

Baker,   Boys1   Book  of  Inventions,   Doubleday  Page  and  Co., 

New  York  City.     Chap.  3  (Wireless). 
Cressey,   Discoveries  and  Inventions  of  the    Twentieth   Century, 

E.  P.  Button  Co.,  New  York  City.     Chap.  17  (Wireless). 
Darrow,  The  Boys'  Own  Book  of  Great  Inventions.     Chaps.  2,  5,  6. 

Macmillan  Co.,  New  York  City. 
Holland,   Historic  Inventions,  G.  W.  Jacobs  Co.,  Philadelphia. 

Chaps.  10  and  15. 
Maule,   Boys'   Book  of    New  Inventions,  Grosset  and  Dunlap, 

New  York  City.     Chap,  n  (Wireless). 
Massie    and    Underbill,    Wireless    Telegraphy    and    Telephony, 

D.  Van  Nostrand  Co.,  New  York  City. 


CHAPTER  XXII 

THE  TELEPHONE 

How  does  the  telephone   differ  from  the  tele- 
graph ? 

Of  all  the  remarkable  inventions  of  the  last  century,  per- 
haps none  quite  equals  the  telephone.  Probably  none  has 
become  so  directly  interwoven  with  the  daily  life  of  so  many 
people.  In  1917  there  were  in  this  country  about  10,000,000 
telephones,  or  one  to  every  ten  inhabitants,  or  one  to  every 
two  families.  In  ten  years  the  number  has  more  than  trebled. 
In  1915  there  were  in  this  country  670,000  miles  of  pole  lines 
and  19,000,000  miles  of  wire.  It  has  been  estimated  that 
about  forty  million  conversations  take  place  every  day  over 
the  telephone,  that  is,  about  thirteen  billion  yearly,  or  an 
average  of  130  to  every  person  in  the  United  States.  The 
telephone  has  revolutionized  our  way  of  living  and  doing 
business. 

In  New  York  City  alone  there  were  in  1917,  682,000  tele- 
phones. This  city  maintains  52  exchanges,  employing  5000 
girls.  Between  the  hours  of  five  and  six  in  the  morning, 
two  thousand  people  are  using  the  telephone,  between  seven 
and  eight,  25,000  people,  and  by  eleven  o'clock,  180,000 
calls  per  hour  are  being  answered.  Long  distance  con- 
versations too  are  common.  In  1909,  18,000  conversations 
were  held  between  New  York  and  Chicago,  or  an  average 
of  50  per  day. 

Uses  of  the  telephone.  The  telephone  finds  use  in  almost 
every  walk  of  life  where  the  human  voice  is  used,  and  makes 

333 


334  SCIENCE  OF  HOME  AND   COMMUNITY 

it  possible  for  all  kinds  of  business  to  be  done  much  more 
quickly.  Large  hotels  are  equipped  with  a  complete  system 
of  telephones.  Stores  of  all  descriptions  receive  a  large 
share  of  orders  by  telephone.  When  Benjamin  Franklin 
was  postmaster  general  at  Philadelphia,  it  required  at  least 
three  weeks  to  send  a  letter  by  mail  to  Boston  and  receive 
an  answer.  Now  the  two  cities  are  connected  by  telephone, 
and  one  may  in  less  than  five  minutes  transact  business  which 
required  three  weeks,  or  5000  times  as  long,  a  century  ago. 

Factories  and  mines  are  equipped  with  telephones  which 
allow  the  work  to  be  controlled  from  a  central  office.  Some 
railroads  are  now  using  it  in  place  of  the  telegraph  in  dis- 
patching trains. 

Many  of  the  larger  newspapers  are  equipped  to  gather 
news  by  means  of  telephone  instead  of  telegraph.  For 
every  edition  of  the  New  York  World  there  has  been  an 
average  of  750  telephone  messages.  The  United  Press  has 
devised  a  method  by  means  of  which  news  is  telephoned  at 
one  time  over  one  wire  to  ten  or  twelve  newspapers  situated 
in  as  many  different  towns. 

In  emergencies  the  telephone  is  of  special  value,  as  in 
cases  of  sickness,  fire,  or  burglary.  In  our  large  cities  it  is 
possible  to  reach  the  entire  police  force  by  use  of  a  system 
of  telephones.  In  times  of  war  a  string  of  telephone  wires 
enables  the  generals  to  control  the  actions  of  their  soldiers. 

The  telephones  on  farms.  There  has  been  a  great  in- 
crease of  the  use  of  the  telephone  on  farms,  and  it  is  doing 
much  to  lessen  the  isolation  of  farm  life.  In  1910  there  were 
2,000,000  telephones  in  farmhouses.  Every  fourth  farmer 
has  a  telephone  which  puts  him  in  touch  with  his  neighbors 
and  markets.  The  telephone  is  of  great  aid  to  the  farmer 
in  marketing  his  produce,  especially  his  perishable  crops. 
It  is  of  special  value  also  in  case  of  emergency  in  calling  for 
help.  For  example,  in  1909  a  three  million  dollar  fruit  crop 
was  saved  in  Colorado  by  use  of  the  telephones.  One  spring 


THE  TELEPHONE  335 

when  the  trees  were  in  flower  the  owners  learned  from  the 
Weather  Bureau  through  the  telephone  that  a  frost  was 
coming  that  night,  which  would  injure  the  blossoms.  The 
farmers  telephoned  to  the  towns  for  help  to  come  and  assist 
in  lighting  smudge  pots  to  ward  off  the  frost.  In  this  way 
the  crop  was  saved. 

Effect  of  the  telephone.  The  telephone  has  had  a  most 
important  effect  on  the  development  of.  the  country  and 
on  the  spirit  of  its  people.  It  has  helped  to  make  a  unity 
of  feeling  and  maintain  a  spirit  of  cooperation  that  would 
not  have  been  possible  without  it.  It  has  helped  to  obliter- 
ate narrow  state  and  sectional  lines,  and  to  develop  a  national 
spirit  that  makes  us  one  people  and  one  nation.  It  has  a 
broadening  and  educative  effect.  It  has  been  the  climax 
of  those  recent  inventions  which  have  helped  to  bring  people 
closer  together.  Railways  and  steamboats  carry  letters, 
the  telegraph  transmits  messages  instantly,  but  greatest  of 
all  is  the  telephone,  which  brings  men  practically  face  to 
face,  carries  speech  over  the  electric  wire,  and  makes  message 
and  answer  both  instantaneous. 

History  of  the  telephone.  The  inventor  of  the  telephone 
was  Alexander  G.  Bell.  He  was  born  in  Scotland  and  moved 
to  Canada  when  he  was  twenty- three  years  old.  Two  years 
later  he  moved  to  this  country  and  became  a  professor  in 
Boston  University.  For  several  years  he  worked  on  his 
idea  of  some  method  of  direct  communication  by  means  of 
the  voice  at  a  distance.  In  1876  he  finally  succeeded  in 
making  an  instrument  which  would  carry  the  human  voice. 
He  obtained  a  patent  on  this  immediately  and  in  the  same 
year  exhibited  it  at  the  Centennial  Exhibition  at  Philadel- 
phia. Here  it  received  much  praise  and  attention.  At 
first  it  was  generally  regarded  as  a  toy  without  practical 
application.  In  getting  the  telephone  started  as  a  com- 
mercial proposition  Bell  and  his  friends  who  were  financing 
the  proposition  had  considerable  difficulty. 


336 


SCIENCE  OF  HOME  AND   COMMUNITY 


The  first  public  telephone  line  was  installed  in  1877  in 
the  state  of  Massachusetts  and  by  the  end  of  the  year  there 
were  778  telephones.  It  was  not  until  1880  that  the  Bell 
Telephone  Company  was  well  established.  At  first  the 
telephone  could  be  used  only  over  short  distances,  but  im- 
provements were  made  so  that  it  could  be  used  over  longer 
and  longer  distances.  The  first  inter-city  line  was  built 
between  Boston  and  Lowell.  A  few  years  later  Boston  and 
New  York  were  connected  by  telephone,  in  1893  New  York 
and  Chicago,  and  still  more  recently  conversation  has  been 
carried  on  between  Boston  and  Denver,  a  distance  of  about 


FIG.  137.  —  First  Bell  telephone. 


2500  miles,  and  finally  between  New  York  and  San  Francisco, 
a  distance  of  about  3  500  miles.  During  all  this  time  improve- 
ments have  constantly  been  made  on  the  telephone,  and  the 
Bell  Company  hires  several  hundred  experts  who  devote 
their  time  to  experimentation  in  order  to  find  possible  im- 
provements. 

Periods  of  the  telephone.  The  history  of  the  telephone 
may  be  divided  into  four  periods.  The  first  period  from 
1876  to  1886  was  one  of  experiments.  The  instruments 
used  were  very  crude  and  imperfect.  Iron  wire,  poor  trans- 
mitters, overhead  wires,  and  boy  operators  were  used. 

The  second  period  from  1886  to  1896  was  one  of  develop- 
ment. During  this  period  great  improvements  were  made 


THE  TELEPHONE  337 

and  the  telephone  reached  a  high  degree  of  efficiency.  Copper 
wire,  underground  cables,  long  distance  lines,  and  girl  opera- 
tors were  innovations  of  this  period. 

The  period  from  1896  to  1906  was  one  of  expansion. 
This  was  the  period  of  business,  when  profits  were  made  as 
a  result  of  previous  toil  and  investments.  During  this 
period  there  appeared  the  pay  station,  the  farm  line,  and  the 
private  branch  exchange. 

The  period  from  1906  to  1916  was  one  of  organization. 
During  this  period  the  telephone  has  reached  out  into  ever 
broadening  fields  till  it  has  become  truly  national  in  scope. 

How  the  telephone  works.  Having  seen  something  of 
the  history  and  uses  of  the  telephone,  let  us  now  try  to  under- 
stand how  it  is  constructed  and  how  it  works.  Like  the 
telegraph  it  uses  electricity,  yet  in  principle  it  is  quite  dif- 
ferent. In  the  telegraph  the  circuit  can  be  opened  and 
closed,  and  the  signals  sent  in  this  way;  but  in  the  tele- 
phone the  voice  is  not  strong  enough  to  do  this.  A  current 
is  passing  through  the  wire  all  the  time  and  the  voice  causes 
variations  in  the  strength  of  the  current. 

In  the  telephone,  it  is  not  sound  vibrations  that  travel 
along  the  wire,  but  an  electric  current. 

With  the  telegraph,  the  earth  can  be  used  as  a  return 
wire,  thus  saving  the  expense  of  one  wire,  but  with  the  tele- 
phone two  wires  are  generally  used,  because  the  telephone 
is  so  sensitive  that  it  would  be  interfered  with  by  various 
disturbances  that  might  develop  in  the  earth. 

Receiver  and  transmitter.  In  the  simplest  form  of  tele- 
phone first  used,  one  piece  of  apparatus  served  both  as 
transmitter  and  receiver.  Figure  138  shows  the  construction 
of  this.  It  consists  of  a  U-shaped  magnet  which  has  around 
each  pole  a  coil  C  of  many  turns  of  very  fine  wire  which  is 
connected  with  the  outside  circuit.  Just  in  front  of  the  mag- 
net is  a  thin  diaphragm  D  made  of  metal.  As  one  speaks 
into  the  transmitter  the  air  waves  produced  by  the  voice 
z 


338 


SCIENCE   OF  HOME   AND    COMMUNITY 


FIG.  138.  —  Bell  telephone 
receiver. 


cause  the  diaphragm  to  vibrate  back  and  forth.     This  vibra- 
tion across  the  magnetic  field  of  the  magnet  induces  currents 

In  the  coil  of  wire,  first  in  one  direc- 
tion and  then  another,  the  strength 
depending  on  the  distance  the  dia- 
phragm moves.  These  varying 
currents  travel  to  the  other  end 
of  the  line  and  cause  the  magnet 
to  attract  the  diaphragm  and  give 
it  the  same  motions  as  those  of 
the  first  diaphragm  which  started 
the  variations  in  the  current.  In 
this  way  the  second  diaphragm 
makes  the  same  vibrations  as  the 
first,  and  hence  it  reproduces  the 
same  sounds. 

This  form  of  telephone  can  be 
used  for  only  short  distances.  The  modern  telephone  has 
been  modified  in  several  ways.  In  the  first  place,  another 
instrument  has  been  introduced  to  serve  as  the  transmitter. 
The  receiver  is  about  the  same  as  that  first  used,  except  that 
a  U-shaped  magnet  is  used  in  place  of  a  single  magnet. 

Carbon  transmitter.  The  carbon  transmitter  is  the  form 
most  commonly  used  (figure  139). 
Back  of  the  diaphragm  D  is  some 
granular  carbon  G  in  a  little  box  C, 
and  as  the  diaphragm  vibrates,  it 
causes  a  variation  in  the  pressure 
upon  the  points  of  carbon.  This  pro- 
duces a  variation  in  the  strength  of 
the  current  that  passes  through  the 
battery.  This  is  connected  with  an 
induction  coil  Ic  (figure  140),  and 
produces  in  the  secondary  coil  varying  currents,  which  travel 
over  the  main  line.  These  variations  are  reproduced  in  the 


FIG.  139.  —  Carbon  trans- 
mitter. 


THE  TELEPHONE 


339 


receiver  at  the  other  end  and  produce  corresponding  varia- 
tions in  the  vibrations  of  the  diaphragm. 

The  induction  coil  just  referred  to  is  another  addition  to 
the  original  telephone.  This  is  necessary  in  order  to  pro- 
duce a  current  of  sufficient  force  to  operate  over  long  dis- 
tances. The  current  is  usually  furnished  by  a  battery  at 
the  central  stations,  instead  of  by  a  local  battery. 

The  telephone  is  a  very  sensitive  instrument.  In  some 
cases  the  distance  through  which  the  diaphragm  moves  is 


ihe 


Transmitter 

IVI'l1^  Receiver 

FIG.  140.  —  Local  battery  telephone  system. 

only  one  ten-millionth  of  an  inch.  To  send  a  telephone 
message  requires  less  than  a  hundred-millionth  part  of  the 
current  required  for  a  telegraphic  message.  So  small  is  the 
amount  of  current  necessary  to  operate  the  receiver,  that  if 
all  the  work  done  in  lifting  the  receiver  off  the  hook  one  foot 
were  changed  into  electric  energy,  it  would  furnish  enough 
electricity  to  operate  the  receiver  continually  for  100,000 
years. 

DEMONSTRATION  26 

Purpose.     To  study  the  working  of  the  telephone. 

Apparatus.  Galvanometer,,  bar  magnet,  coil  of  wire  wound 
in  form  of  a  spool.  Demonstration  form  of  dissectible  tele- 
phone. 

Directions.  I.  Secure  a  coil  of  wire  wound  on  a  spool  and 
provided  with  binding  posts.  Connect  these  with  a  galvanom- 
eter. Place  a  bar  magnet  inside  the  coil.  Bring  a  piece  of 
soft  iron  near  the  magnet.  Does  the  needle  move?  Take 
the  iron  away.  Is  any  current  generated  ? 


340 


SCIENCE   OF  HOME  AND    COMMUNITY 


2.    Make  a  study  of  the  parts  of  a  dissectible  telephone. 
Make  a  drawing  and  explain  the  use  of  each  part. 

Central.     One  of  the  most  interesting  parts  of  a  telephone 
system  is  the  central  station,  where  connections  are  made 

for  different  sub- 
scribers. When  a 
subscriber  takes  his 
receiver  from  the 
hook,  a  little  lamp 
glows  opposite  the 
hole  that  is  marked 
with  this  person's 
number ;  this  is  a 
signal  to  the  operator 
that  some  one  wishes 
a  connection  made. 
The  operator's  re- 
ceiver and  transmit- 
ter are  fastened  to 
her  head  and  neck,  so 
that  both  her  hands 
are  free.  She  con- 
nects her  wire  with 
the  subscriber's  by 
means  of  a  plug,  and 
having  found  the  de- 
sired number  makes 
the  necessary  connec- 
tions. This  is  done 
by  inserting  a  plug 

connecting  with  the  first  subscriber's  telephone  into  a  hole 
connecting  with  the  second  subscriber's  telephone.  By 
pressing  a  button  she  causes  a  bell  to  ring  on  the  second 
subscriber's  telephone.  When  the  second  receiver  is  taken 


FIG.  141.  —  Central  making  connections.  Each 
dot  on  the  board  is  a  subscriber's  connection. 
The  cords  connect  one  subscriber  with  another. 
The  switches  for  operator's  phone  and  the  pilot 
lamps  showing  when  a  subscriber  wishes  a  con- 
nection are  set  in  the  table. 


THE   TELEPHONE  341 

from  the  hook,  a  second  light  glows  before  the  operator,  and 
the  two  lights  continue  to  glow  as  long  as  the  telephones  are 
being  used.  When  the  receivers  are  hung  up,  the  lights 
go  out ;  this  is  a  signal  to  the  operator,  who  then  pulls  out 
the  plugs. 

The  cords  containing  the  connecting  wires  are  weighted 
and  hung  below,  so  that  when  a  plug  is  taken  out  of  a  hole 
the  wires  fall  back  into  their  places  automatically,  out  of 
the  way  and  ready  for  the  next  call.  Practice  enables  these 
girls  to  work  with  astonishing  rapidity.  In  the  best  ex- 
changes they  answer  a  call  in  an  average  time  of  3-J  seconds. 

For  out-of-town  calls,  connection  is  made  with  "  Long 
Distance,"  who  makes  the  connection  in  much  the  same  way 
as  that  already  described.  A  record  of  the  time  occupied 
by  the  conversations  is  kept  by  means  of  an  automatic  time 
stamp.  Charges  are  made  according  to  the  time  that  the 
line  is  in  use. 

FIELD  EXERCISE  7 

Purpose.     To  visit  the  central  telephone  office. 

Directions.  Arrangements  can  usually  be  made  with  the 
superintendent  of  the  telephone  exchange  to  allow  the  class  to 
visit  the  central  office.  Here  some  one  can  explain  the  work  of 
the  operators  and  the  construction  of  the  central  telephone 
outfit.  At  the  next  meeting  of  the  class  the  points  observed 
should  serve  as  a  basis  for  discussion. 

Wireless  telephone.  Now,  most  wonderful  of  all,  comes 
the  wireless  telephone,  by  means  of  which  people  may  talk 
with  each  other  at  a  distance  without  any  wires  between. 
The  more  recent  development  of  the  wireless  telephone  has 
been  largely  the  work  of  Americans.  In  1900  the  wireless 
was  first  successfully  used  for  a  distance  of  one  mile,  although 
the  sounds  reproduced  were  not  satisfactory.  The  mechan- 
ism was  gradually  perfected  so  that  it  was  used  over  longer 
distances,  and  the  sound  was  reproduced  more  exactly,  until 


342  SCIENCE   OF  HOME   AND    COMMUNITY 

it  is  superior  to  the  ordinary  telephone  in  the  distinctness 
and  fidelity  with  which  sounds  are  reproduced. 

Talking  over  long  distances.  In  1907  speech  was  trans- 
mitted from  Massachusetts  to  Washington,  D.  C.,  a  distance 
•of  400  miles.  In  May,  1915,  this  was  increased  to  1000 
miles,  the  distance  from  Long  Island  to  Georgia.  Later  in 
the  year  communication  was  made  between  Washington, 
D.  C.,  and  the  Eiffel  tower,  Paris.  The  climax  was  reached 
in  the  same  year  when  a  message  spoken  into  the  telephone 
receiver  at  Washington  was  heard  at  San  Francisco,  a  dis- 
tance of  2500  miles  and  also  at  the  Hawaiian  Islands,  a 
distance  of  4900  miles.  This  is  farther  than  conversation 
has  been  carried  on  by  means  of  the  wire  telephone.  Science 
had  found  a  means  by  which  a  person  speaking  in  an  ordinary 
tone  of  voice  could  have  this  reproduced  so  that  its  owner 
could  be  recognized  at  a  distance  equal  to  one  fifth  the  cir- 
cumference of  the  globe.  If  the  sound  waves  themselves 
could  have  traveled  that  distance,  it  would  have  required 
more  than  six  hours,  but  the  electric  waves  covered  the  dis- 
tance in  a  small  fraction  of  a  second. 

This  message  went  out  not  only  to  the  west  but  in  every 
direction ;  so  that  any  one  within  a  radius  of  4900  miles  of 
Washington  could  have  heard  the  message  had  he  been 
provided  with  the  necessary  instruments.  This  message, 
then,  could  have  been  heard  in  all  the  great  cities  of  Europe, 
—  in  Paris,  London,  Berlin,  Rome,  and  Petrograd,  and  in 
Rio  Janeiro  in  South  America,  or  at  the  North  Pole.  It 
would  have  been  possible  for  people  in  the  United  States 
to  talk  with  their  friends  in  the  trenches  in  France,  if  both 
had  been  provided  with  suitable  instruments. 

Combination  of  common  and  wireless  telephone.  Another 
remarkable  thing  that  has  been  accomplished  is  to  connect 
up  the  wire  telephone  with  the  wireless  so  that  they  can 
both  be  used.  A  man  in  New  York  City  talked  into  an 
ordinary  telephone  receiver  as  far  as  Washington  by  wire, 


THE  TELEPHONE  343 

and  from  there  the  waves  were  sent  out  into  the  ether  and 
connection  made  with  San  Francisco  by  wireless.  It  is 
possible  to  have  this  taken  up  again  by  a  wire  telephone. 
So  that  the  possibilities  of  the  future  are  that  a  person  living 
at  Chicago,  or  some  other  inland  city,  may  telephone  di- 
rectly to  a  person  in  Paris.  The  message  will  first  travel 
by  wire  to  some  wireless  station  on  the  Atlantic  coast,  then 
by  wireless  to  some  coast  station  in  Europe,  and  then  by 
wire  to  Paris,  without  interruption. 

Uses  of  wireless  telephone.  The  possibilities  that  are  thus, 
suggested  sound  almost  like  fairy  tales  and  fairly  stagger 
the  imagination.  It  does  not  seem  probable  now  that  wire- 
less will  take  the  place  of  the  ordinary  short-distance  tele- 
phone, but  will  rather  work  with  it  and  make  it  more  effec- 
tive. The  two  working  together  will  make  a  universal 
telephone.  The  wireless  telephone  has  certain  special 
fields  with  which  the  ordinary  telephone  cannot  compete.- 
Chief  among  these  is  telephony  from  continent  to  continent, 
across  the  ocean.  Other  fields  are  in  telephony  from  ship 
to  ship  and  between  ship  and  shore.  Battleships  of  navies 
and  some  airplanes  are  now  provided  with  wireless  outfits. 
In  the  .near  future  it  will  doubtless  be  possible,  as  one  travels 
on  the  ocean  steamers,  to  keep  in  touch  by  telephone  with 
his  friends  during  the  entire  journey  across. 

Outfits  on  trains.  Already  these  outfits  have  'been  in- 
stalled on  trains,  and  it  is  possible  for  one  to  telephone  from 
a  train  while  it  is  traveling  at  the  rate  of  fifty  miles  an  hour. 
In  this  way  conversations  have  been  carried  on  through  a 
distance  of  fifty-two  miles.  But  this  device  will  be  used 
chiefly  for  directing  the  movements  of  trains,  which  can 
by  this  means  receive  orders  without  stopping. 

Advantages  of  wireless  over  ordinary  telephone.  For  long 
distance  transmission  the  wireless  telephone  has  many  ad- 
vantages over  the  wire  telephone.  It  is  much  cheaper  to 
install,  as  there  are  no  poles  or  wires.  It  costs  less  to  main- 


344  SCIENCE  OF  HOME  AND   COMMUNITY 

tain  it,  as  it  requires  fewer  employees  and  there  is  not  so 
much  outfit  to  keep  in  repair.  There  would  be  fewer  break- 
downs, as  there  would  be  no  wires  to  be  exposed  to  storms, 
and  the  breakdowns  that  did  occur  could  be  more  easily 
found  and  repaired.  And  furthermore,  it  transmits  speech 
more  distinctly  and  perfectly. 

Disadvantage  of  wireless.  The  wireless  telephone  has  one 
great  disadvantage,  however.  It  is  found  that  the  efficiency 
of  its  working  varies  from  day  to  day,  owing  to  natural  elec- 
trical disturbances.  This  does  not  matter  so  much  for  short 
distances ;  but  for  long  distances  it  is  a  serious  matter, 
since  unfavorable  conditions  may  prevent  the  telephone 
from  working  at  all.  It  is  not  possible  now  to  use  the  wire- 
less in  cities  where  there  are  many  telephones  in  close  prox- 
imity. It  does  not  seem  probable  that  wireless  will  take 
the  place  of  wire  telephone  for  local  use. 

Construction  and  operation  of  wireless  telephone.  We  may 
next  inquire  regarding  the  construction  and  method  of 
operation  of  this  wonderful  instrument  that  can  send  the 
human  voice  across  the  ocean.  There  are  three  essential 
parts  to  a  wireless  telephone  :  first,  a  machine  to  start  waves 
in  the  ether  ;  second,  a  device  by  means  of  which  the  voice 
can  control  these  waves ;  and  third,  a  receiver  for  detecting 
the  waves  and  changing  them  into  sound. 

There  is  the  same  difference  between  the  wireless  tele- 
phone and  telegraph  that  there  is  between  the  ordinary 
telephone  and  ordinary  telegraph.  In  both  telegraphs  the 
circuit  is  interrupted  by  means  of  a  key.  In  both  telephones 
there  is  a  continuous  current,  and  connected  with  this  is  a 
telephone  transmitter. 

A  number  of  different  devices  have  been  used,  but  we  will 
undertake  to  understand  only  the  general  principle.  The 
human  voice,  by  means  of  the  air  waves,  sets  the  diaphragm 
of  the  telephone  into  vibration.  As  this  disk  vibrates,  it 
causes  a  change  in  the  current.  This  varying  current  is 


THE   TELEPHONE  345 

used  to  send  out  waves  through  the  ether  in  every  direction. 
These  waves  are  picked  up  by  a  sensitive  receiving  apparatus, 
which  sets  in  motion  another  diaphragm  with  vibrations 
corresponding  to  the  sending  diaphragm,  and  thus  the 
original  sound,  with  all  its  tones  and  quality,  is  reproduced. 

Types  of  transmitters.  A  variety  of  transmitters  have 
been  devised  for  controlling  the  current.  One  is  very  much 
like  the  ordinary  carbon  microphone  transmitter.  In  an- 
other form,  called  an  audion,  a  flame  is  used  as  a  part  of 
the  circuit,  as  it  is  found  to  be  very  sensitive  to  electric 
waves.  Still  another  depends  on  the  fact  that  the  elec- 
trical resistance  of  selenium  depends  on  the  amount  of  light 
that  strikes  it.  This  is  'used  in  connection  with  an  arc 
lamp. 

The  sending  station  has  aerial  wires  like  a  telegraph  station 
and  may  send  out  continuous  electric  waves ;  or  it  may  send 
out  a  discontinuous  set  of  waves  caused  by  sparks,  which 
vibrate  so  rapidly  that  they  cannot  be  heard,  and  do  not 
affect  the  telephone  diaphragm.  This  vibration  frequently 
may  vary  from  40,000  to  100,000  per  second. 

Tuning.  The  wireless  telephone  has  the  same  problem 
of  tuning  as  the  wireless  telegraph.  This  difficult  problem 
has  been  partially  solved,  so  that  a  receiving  instrument 
can  receive  a  message  only  when  it  is  tuned  to  correspond 
to  the  sending  instrument. 

SUPPLEMENTARY  QUESTIONS   FOR  CLASS  DISCUSSION 

1.  Which  is  more  useful  to  man,  the  telegraph  or  the  tele- 
phone ? 

2.  What  has  been  the  history  of  the  development  of  the 
telephone  ? 

3.  How  are  the  receiver  and  transmitter  constructed? 

4.  How  are  the  connections  made  at  central  ? 

5.  How  does  the  wireless  telephone  differ  from  the  ordinary 
telephone  ? 


346  SCIENCE   OF  HOME   AND    COMMUNITY 

6.  How  does  the  wireless  telephone  differ  from  the  wireless 
telegraph  ? 

7.  What  are  the  possibilities  of  future  uses  for  the  wireless 
telephone  ? 

REFERENCES 

Carson,  History  of  the  Telephone,  A.  C.  McClure  Co.,  Chicago. 
Darrow,   The  Boys'  Own  Book  of  Great  Inventions,  The  Macmillan 

Co.,  New  York  City.     Chaps.  3,  4,  7. 
Doubleday,    Stories    of    Inventors,    Doubleday    Page    and    Co., 

New  York  City.     Pages  181-199. 
Harper's  Electricity  Book  for  Boys,  Harper  Bros.,  New  York 

City.     Chap.  8. 
Holland,   Historic  Inventions,  G.  W.  Jacobs  Co.,  Philadelphia. 

Chap.  13. 
Johnson,    Modern  Inventions,  F.  A.  Stokes  Co.,  New  York  City. 

Chap.  14  (Wireless). 
Massey   and   Underbill,    Wireless     Telegraphy   and     Telephony, 

D.  Van  Nostrand  Co.,  New  York  City. 


SECTION  C 
THE  HEALTH  OF  THE  COMMUNITY 


CHAPTER  XXIII 
THE  PUBLIC  WATER,  MILK,  AND  FOOD  SUPPLY 

1.  What  may  communities  do  to  protect  their 
water  supply  ? 

2.  Why  should  the  milk  supply  of  a  city  be  care- 
fully inspected  ? 

3.  In  what  ways  may  foods  be  made  unfit  to 
eat? 

Water  supply.  The  first  and  most  important  duty  to 
which  a  community  should  give  its  attention  is  the  protec- 
tion of  its  health.  One  of  the  first  things  to  do  is  to  obtain 


FIG.  142.  —  Water  supply  system  for  towns  and  cities. 

a  pure  water  supply.  As  all  people  in  a  city  are  using  water 
from  the  same  source,  an  impure  water  supply  affects  all 
the  people  in  the  community.  The  city  water  supply  may 
be  obtained  from  two  sources,  ground  water  from  artesian 

347 


348  SCIENCE  OF  HOME  AND   COMMUNITY 

wells,  and  surface  water  from  lakes  and  rivers.  The  chief 
kind  of  impurity  against  which  the  water  must  be  protected 
is  the  disease  germ.  One  of  the  commonest  of  these  germs 
found  in  water  is  the  one  that  causes  typhoid  fever.  Many 
cases  of  typhoid  are  due  to  impure  water. 

How  it  is  made  impure.  Drinking  water  may  be  con- 
taminated by  typhoid  germs  in  a  number  of  ways.  In 
every  case  some  one  with  typhoid  fever  is  the  source  of  the 
germs,  which  are  given  off  in  the  wastes  of  the  -body.  Some- 
times the  sewage  containing  these  germs  may  empty  into  a 
river,  and  then  the  water  from  this  river  may  be  used  as 
drinking  water  by  a  city  situated  further  down  the  river,  as 
on  the  Merrimac  River  in  New  England.  A  city  may 
discharge  its  sewage  into  a  lake  and  take  drinking  water  from 
the  same  lake  near  the  sewer  outlet,  as  was  formerly  done  in 
Cleveland,  Ohio.  Even  the  water  of  an  artesian  well  has 
been  known  to  be  contaminated  through  a  leak  in  the  water 
pipes,  through  which  sewage  entered  when  a  flooded  con- 
dition of  the  river  brought  the  river  water  in  contact  with 
these  pipes,  as  happened  some  years  ago  in  Mankato,  Minn. 
In  Plymouth,  Pa.,  an  epidemic  occurred  because  a  family 
living  on  the  banks  of  the  stream  from  which  the  town  took 
its  water  had  thrown  the  wastes  from  a  typhoid  patient  on 
the  snow  near  the  stream.  When  this  melted,  the  germs 
were  carried  into  the  stream. 

All  these  cases  go  to  show  how  important  it  is  to  prevent 
contamination  of  the  water  supply,  because  typhoid  is  a 
preventable  disease,  due  to  carelessness,  and  many  cases 
may  be  avoided  by  keeping  the  water  supply  pure. 

Purification  by  filter  beds.  When  there  is  a  possibility 
that  water  may  be  polluted,  it  can  be  made  clean  by  filter- 
ing, and  this  is  being  done  by  many  cities.  Sand  filters  are 
the  means  which  modern  science  has  found  for  purifying 
water.  These  filters  are  four  or  five  feet  thick  and  are 
spread  out  over  several  acres.  On  top  is  a  layer  of  fine  sand, 


THE   PUBLIC  WATER,   MILK,   AND   FOOD    SUPPLY      349 


below  this  a  layer  of  coarse  sand  and  then  layers  of  gravel, 
pebbles,  and  stones.  Pipes  are  placed  beneath  to  carry  off 
the  purified  water.  The  filter  beds  are  flooded  with  water, 
which  soaks  through  and  comes  out  below  purified.  Not 
only  have  the  larger  particles  been  filtered  out,  but  what  is 
of  much  greater  importance,  the  water  has  been  freed  of 
bacteria  and  decaying  organic  material. 

Strange  as  it  may  seem,  the  work  of  clearing  the  foul 
water  of  the  injurious  bacteria  is  done  by  other  bacteria  that 
are   beneficial,  which  live 
on  the  small  grains  of  sand 
•  and  attack  and  destroy  the 
harmful  bacteria  as  they 
pass  through  the  filter.   In 
order  that  these  bacteria 
may  work  to  best  advan- 


FIG.  143.  —  Cross-section  of  a  sand  filter. 


tage,  they  must  have  the 
oxygen  found  in  the  air,  so 
that  if  the  water  is  very 
foul,  it  is  not  allowed  to 
cover  the  filter  beds  all  the  time.  But  it  is  occasionally  drained 
off  so  that  the  bed  may  be  exposed  and  the  bacteria  given  a 
chance  to  get  oxygen  in  the  air.  The  sand  filter  operates 
slowly  and  therefore  many  of  the  large  cities  now  use  rapid 
filter  beds  with  alum  and  hypochlorite.  Following  are  two 
instances  in  which  large  municipalities  have  found  means 
of  reducing  the  death  rate  by  securing,  under  adverse  con- 
ditions, a  supply  of  pure  water. 

Cleveland,  Ohio.  Cleveland  took  its  drinking  water  from 
Lake  Erie  and  formerly  emptied  its  sewage  into  the  same 
lake  not  far  from  where  the  water  was  taken  in.  As  the  city 
grew  larger,  the  number  of  cases  of  typhoid  fever  increased, 
till  finally  such  an  epidemic  broke  out  that  people  became 
frightened  and  the  city  authorities  saw  that  something  must 
be  done.  Accordingly  experts  were  called  in  to  study  the 


350 


SCIENCE  OF  HOME  AND   COMMUNITY 


situation.  They  found  that  the  currents  of  the  lake  were 
carrying  some  of  the  sewage,  containing  its  typhoid  fever 
germs,  to  the  part  of  the  lake  from  which  water  was  taken 
for  drinking.  So  the  city  had  the  inlet  for  the  water  ex- 
tended miles  out  into  the  lake,  and  the  outlet  for  the  sewers 
placed  at  such  a  distance  from  the  intake  that  the  sewage 
could  not  reach  it.  As  soon  as  this  work  was  completed, 
the  number  of  cases  of  typhoid  fever  decreased  at  once  and 


1890  1895  1900  1905  1910     1912 

FIG.  144.  —  Effect  of  filtering  water  on  typhoid  death  rate. 

within  a  year  the  number  of  deaths  was  only  one  eighth  as 
many. 

Lawrence,  Mass.  Lawrence  is  situated  on  the  Merrimac 
River.  Nine  miles  above  on  the  same  river  is  the  city  of 
Lowell,  and  above  Lowell  are  still  other  cities.  Each  of 
these  cities  takes  its  drinking  water  from  the  river  above  it 
and  pours  its  sewage  into  the  river  below  it.  Thus  each 
city  gets  in  its  drinking  water  some  rof  the  sewage  of  the 
cities  above  it.  The  lower  cities  on  the  river  were  especially 
subject  to  typhoid  fever.  Whenever  Lowell  had  an  out- 


THE  PUBLIC  WATER,   MILK,  AND   FOOD    SUPPLY      351 

break,  one  was  sure  to  follow  in  Lawrence.  People  soon 
learned  that  the  reason  was  that  the  bacteria  from  the  sick 
people  in  Lowell  were  carried  down  the  river  ftito  the  drink- 
ing water  of  Lawrence.  After  a  careful  study  of  the  situa- 
tion, the  people  of  Lawrence  decided  to  put  in  large  outdoor 
filters  in  order  that  the  river  water  might  pass  through  these 


FIG.  145.  —  Cases  of  typhoid  par  100,000  inhabitants  before  filtering  water  supply 
(solid)  and  after  (shaded)  in  A,  Watertown,  N  Y.  ;  B,  Albany,  N.  Y.;  C,  Law- 
rence, Mass.  ;  D.  Cincinnati,  Ohio. 

and  be  purified  before  it  was  used  by  the  people  of  the  city. 
These  filters  worked  so  well  in  taking  out  the  typhoid  germs 
that  only  one  fifth  as  many  people  died  each  year  from 
typhoid  fever  as  had  formerly  (see  figure  145),  and  when  the 
next  epidemic  of  the  disease  appeared  in^  Lowell,  Lawrence 
was  not  affected. 


DEMONSTRATION  27 

Purpose.  To  see  which  kinds  of  water  contain  the  fewest 
bacteria. 

Materials.  Sterilized  test  tubes  containing  culture  medium, 
pipette,  petri  dishes. 

Directions,  i.  The  culture  medium  can  be  bought  all  pre- 
pared from  dealers  directly,  or  through  drug  stored.  It  can 
also  be  made  as  explained  in  Conn's  Bacteria,  Yeasts  and 


352  SCIENCE  OF  HOME  AND   COMMUNITY 

Molds  in  the  Home.  It  will  be  convenient  to  melt  the  culture 
and  fill  a  number  of  sterilized  test  tubes  about  half  full.  Plug 
each  tube  with  cotton  batting. 

2.  Obtain  several  samples  of  water,  some  from  the  faucet, 
some  from  a  well,  some  from  bottled  water,  some  from  melted 
snow,  some  from  a  river,  some  from  the  street  gutter. 

3.  Take  as  many  culture  tubes  as  the  samples  of  water  to 
be  tested,  place  them  in  a  dish  of  water  and  heat  the  water  till 
the  gelatin  melts.     By  means  of  a  sterilized  pipette  introduce 
i  cc.  of  the  samples  of  water  into  the  various  tubes,  one  tube 
for  each  sample.     Shake  the  tubes  so  as  to  mix  thoroughly  the 
water  and  pour  the  culture  medium  from  each  tube  into  a 
sterilized  petri  dish,  covering  at  once.     Put  a  piece  of  gummed 
paper  on  each  dish  and  label  the  source  of  the  water. 

4.  Allow  to  remain  at  ordinary  temperature  for  two  or  three 
days.     Count    the    number    of    colonies    which    appear.     This 
represents  the  number  of  bacteria  in  the  cubic  centimeter  of 
water.     Which  sample  contained  the  most  ?     Which  the  least  ? 


Milk.  Milk  is  one  of  the  best  foods  that  we  have.  But 
it  is  also  a  medium  most  favorable  to  the  growth  of  bacteria 
and  great  care  should  be  taken  to  see  that  milk  is  clean. 
Milk  is  a  common  means  of  carrying  disease  germs  and  pro- 
ducing epidemics.  An  investigation  made  by  the  surgeon- 
general  of  the  army  showed  that  at  least  500  epidemics  in 
this  country  had  been  traced  to  impure  milk.  Of  these  epi- 
demics, 317  were  of  typhoid  fever,  125  of  scarlet  fever,  and 
51  of  diphtheria.  Tuberculosis  and  tonsillitis  germs  also 
may  be  carried  by  milk.  It  is  thought  that  one  sixth  of 
the  cases  of  typhoid  fever  are  due  to  unclean  milk. 

How  milk  may  carry  diseases.  Cows  may  have  tubercu- 
losis, in  a  form  similar  to  that  found  in  man,  and  these 
cows  may  be  a  means  of  giving  the  disease  to  man  directly 
through  milk  and  meat.  But  most  of  the  disease  germs 
found  in  milk  are  introduced  through  carelessness  after  it 
is  drawn  from  the  cows.  Some  epidemics  of  typhoid  fever 


THE  PUBLIC  WATER,  MILK,  AND   FOOD   SUPPLY     353 


have  been  due  to  the  fact  that  the  milk  cans  were  washed 
in  water  containing  the  disease  germs,  which  grew  and 
multiplied  in  the  milk.  An  epidemic  of  diphtheria  in  one 
city  was  traced  to  a  man  with  a  light  case  of  diphtheria, 
who  was  working  in  the  dairy.  In  another  city  an  epidemic 
of  typhoid  fever  was  found  to  be  due  to  the  fact  that  three 
people  living  in  the  house  connected  with  the  dairy  had  the 
fever,  and  the  dairy  utensils  were  washed  in  the  house  and 
wiped  on  towels  used  by  the  people  there.  In  some  cases 
after  people  have  recov- 
ered from  typhoid  they 
may  continue  for  years  to 
give  off  the  bacteria  caus- 
ing the  disease,  and  if  they 
work  in  a  dairy  they  may 
contaminate  the  milk. 

Milk  inspection.  In 
cities  and  towns  where 
many  people  get  their 
milk  from  a  few  sources, 
inspectors  should  be  ap- 
pointed by  the  town  to 
see  that  only  clean  milk 
is  sold  the  people.  The 
chief  food  of  babies  is 
milk,  and  many  thousands  die  every  year  on  account  of  im- 
pure milk.  In  the  city  of  Rochester,  N.  Y.,  nearly  1000 
children  under  five  years  of  age  died  in  1892.  The  city 
began  an  inspection  of  its  milk  supply,  and  as  a  result  the 
number  of  deaths  of  young  children  decreased  to  less  than 
500  during  1896,  although  the  city  had  increased  in  popu- 
lation. Clean  milk  reduced  the  number  of  deaths  one  half 
and  saved  each  year  the  lives  of  500  children  in  this  city  alone. 

Now  let  us  see  just  what  a  city  should  do  in  order  to  get 
pure  milk  for  its  people.     The  best  way  to  answer  this  is 

2A 


FIG.  146.  —  Pasteurizing  milk. 
(See  page  381.) 


354 


SCIENCE   OF  HOME  AND   COMMUNITY 


to  explain  what  is  actually  being  done  by  many  cities.  In- 
spectors are  appointed  who  go  into  the  country,  examine 
the  dairies,  and  require  the  owners  to  meet  certain  con- 
ditions of  cleanliness  before  they  are  allowed  to  sell  milk. 
If  the  owners  do  not  meet  these  conditions,  their  licenses 
are  taken  away  from  them,  or  they  are  fined.  It  is  vitally 
important  that  no  person  with  a  contagious  disease  be 

connected  with  the  dairy. 

Clean  milk.  The  barn  must 
be  clean,  the  cows  must  be 
cleaned  before  each  milking, 
and  the  milkers  must  be  clean. 
As  soon  as  drawn,  the  milk 
should  be  put  in  a  cool  place  so 
that  it  will  keep  sweet  longer. 
It  is  found  that  the  cleanliness 
of  milk  can  be  tested  by  the 
number  of  bacteria  in  it,  be- 
cause the  more  dirt  in  the 
milk,  the  more  bacteria  get 
in  on  the  dirt.  The  numbers 
of  bacteria  increase  if  the  milk 
is  not  kept  cool,  and  they  also 
increase  with  the  age  of  the 
milk.  Ordinary  milk  may  con- 
tain as  high  as  10,000,000  bac- 
teria per  cubic  centimeter  (about  one  fifth  of  a  teaspoonf ul) . 
Some  idea  of  the  cleanliness  of  milk  and  the  care  given  it 
may  be  obtained  by  finding  out  the  number  of  bacteria 
in  it.  Scientists  have  a  way  of  doing  this.  The  city  of 
Rochester  has  set  a  standard  of  100,000  bacteria  per  cubic 
centimeter  and  does  not  allow  any  milk  to  be  sold  that  con- 
tains more  than  this.  This  leads  the  dairy  men  to  keep 
their  barns  and  cows  clean  and  to  be  careful  in  handling 
the  milk. 


FIG.  147.  —  Sanitary  milking.  (Pail 
scalded,  cow  groomed,  milk  bag 
wiped,  hands  washed.) 


THE  PUBLIC  WATER,  MILK,  AND   FOOD   SUPPLY     355 

Certified  milk.  Some  dairies  sell  certified  milk.  This 
means  that  unusual  care  has  been  given  to  all  the  work  in 
connection  with  the  dairy,  and  as  a  result  unusually  pure 


FIG.  148.  —  Cooling  milk.    This  should  be  done  as  soon  as  drawn. 

milk  is  obtained.  This  milk  is  certified  by  the  inspectors 
and  is  sold  at  a  higher  price  than  ordinary  milk.  But 
every  town  should  have  inspected  milk,  which  means  clean 
milk,  at  the  regular  price. 


DEMONSTRATION  28 

Purpose.  To  compare  the  cleanliness  of  milk  from  different 
sources  by  estimating  the  number  of  bacteria  in  a  cubic  centi- 
meter (cc.). 

Materials.  Several  samples  of  milk.  See  demonstration  27 
and  read  I  under  Directions. 


356  SCIENCE  OF  HOME  AND   COMMUNITY 

Directions,  i.  Pour  100  cc.  of  water  into  a  flask  and  boil 
for  ten  minutes.  When  the  water  cools  add  I  cc.  of  milk  and 
shake  thoroughly. 

2.  Melt  a  tube  of  culture  medium.     Into  this  put  one  drop 
of  the  diluted  milk.     Shake  it  thoroughly.     Pour  into  a  steril- 
ized petri  dish  and  cover. 

3.  Allow  to  stand  for  several  days  and  count  the  number  of 
colonies.     Each  colony  started  from  one  bacterium.     Estimate 
the  number  of   bacteria   in  I    cc.  of   the   undiluted   milk,  re- 
membering that  about  15  drops  make  a  cubic  centimeter  and 
that  i  cc.  of  the  milk  was  diluted  with  100  cc.  of  water. 

4.  Prepare  several  tubes  and  dishes,  putting  in  milk  from 
different  sources.     Also  take  milk  from  the  same  sample  after 
it  has  stood  for  a  day,  because  the  number  of  bacteria  depends 
on  the  age  of  the  milk. 

Foods.  Most  of  our  foods  are  bought  from  public  sup- 
plies, so  that  it  is  not  possible  for  each  individual  to  deter- 
mine for  himself  the  conditions  under  which  foods  have  been 
prepared.  It  is  necessary,  therefore,  to  have  these  matters 
controlled  by  laws,  and  foods  examined  by  men  who  make  it 
a  business  to  inspect  them. 

Diseased  foods.  In  order  to  know  how  best  to  protect 
our  food,  we  must  first  know  what  some  of  the  impurities 
are  that  are  found  in  foods.  Foods  may  be  diseased  or 
decayed.  For  example,  if  cattle  that  have  had  tubercu- 
losis are  killed  and  sent  to  market,  the  meat  contains  the 
germs  and  is  dangerous  as  a  food.  In  the  preparation  and 
marketing  of  foods,  they  may  be  contaminated  with  germs 
through  exposure  to  dust  and  flies  or  by  being  handled  by 
people  who  are  diseased.  Food  may  be  kept  so  long  before 
being  sold  to  the  consumer  that  it  begins  to  decay ;  then 
there  are  formed  certain  poisons  called  ptomaines,  which 
often  cause  serious  sickness  and  even  death. 

Adulteration.  Various  kinds  of  adulterations  are  prac- 
ticed but  the  three  most  commonly  found  are :  first,  the 


THE  PUBLIC   WATER,   MILK,  AND   FOOD   SUPPLY     357 

mixing  of  some  cheaper  material  with  the  original  substance ; 
second,  the  addition  of  coloring  matter ;  and  third,  the  use 
of  chemical  preservatives  to  keep  foods  from  decay. 

Mixture.  The  substances  used  in  the  first  case  are 
usually  not  harmful  to  the  human  system,  but  the  objection 
to  this  method  lies  in  the  fraud  thus  practiced.  Ground 
coffee  may  be  adulterated  with  chicory,  ground  peas,  beans, 
etc. ;  unground  coffee  is  adulterated  less  frequently.  Butter 
may  be  mixed  with  oleomargarine;  water  may  be  added  to 
milk,  or  the  cream  removed;  flavoring  extracts  and  spices 
are  frequently  adulterated. 

Coloring  matter.  There  is  a  difference  of  opinion  whether 
there  are  ill  effects  in  the  body  from  all  of  the  materials  used 
for  coloring  foods.  But  regarding  the  effect  of  many  of 
them  there  is  no  doubt,  as  they  are  known  to  be  injurious. 
There  indisputably  remains  the  fraud,  as  these  colors  are 
used  to  give  a  false  appearance  to  the  foods  containing  them. 
Coloring  matters  may  be  added  to  jellies  made  from  cheap 
substances  so  as  to  give  them  the  same  appearance  as  those 
made  from  good  fruits.  They  may  be  added  to  cucumber 
pickles  and  tomato  catsup  to  bring  back  the  original  color 
which  has  been  lost  in  £he  process  of  canning.  Butter  is 
frequently  artificially  colored.  And  chopped  meats  which 
are  not  fresh  may  have  coloring  matter  added  to  give  them 
the  appearance  of  fresh  meat. 

Preservatives.  The  most  dangerous  kind  of  adulteration 
is  the  use  of  chemical  preservatives,  because  most  of  those 
used  are  injurious  to  health.  Among  the  more  common 
kinds  are  formaldehyde,  benzoic,  boric,  and  salicylic  acids, 
and  their  sodium  salts,  such  as  benzoate  of  soda. 

Milk  is  sometimes  treated  with  preservatives,  especially 
in  warm  weather,  to  delay  its  souring.  Formalin  is  the 
substance  generally  used  for  this  purpose.  Milk  is  the  chief 
food  of  infants,  and  therefore  it  is  specially  important  that 
it  should  be  pure  and  wholesome.  At  that  early  time  in 


SCIENCE  OF  HOME  AND   COMMUNITY 

life,  these  preservatives  are  particularly  dangerous  to  health. 
Impure  milk  is  an  important  factor  in  the  large  infant 
mortality  in  our  large  cities.  An  official  of  the  Health  De- 
partment of  New  York  City  said,  "No  doubt,  if  we  could  get 
pure  milk,  mortality  of  infants  would  decrease  fifty  per  cent." 

In  recent  years  there  has  been  considerable  discussion 
regarding  the  effects  on  the  body  of  benzoate  of  soda.  The 
United  States  government  has  allowed  this  to  be  used  in 
certain  small  quantities  as  a  preservative,  but  there  are 
serious  doubts  regarding  the  wisdom  of  this  action.  Dr. 
Wiley  (in  experimenting  with  his  poison  squad)  found  that 
this  substance  was  injurious  to  the  health  of  those  taking 
it.  The  general  consensus  of  the  best  scientific  and  medical 
opinion  seems  to  be  that  the  use  of  benzoate  of  soda  as  a 
preservative  of  foods  should  not  be  allowed. 

One  of  the  chief  arguments  against  the  use  of  all  kinds 
of  coloring  matters  and  preservatives  lies  in  the  fact  that 
their  use  makes  it  possible  that  substances  be  canned  and 
sold  which  are  entirely  unfit  for  food.  For  instance,  in  the 
canning  of  tomatoes  and  catsups,  if  the  substances  are 
allowed  to  stand  too  long  or  are  not  cared  for  in  a  clean  way, 
the  mixture  ferments  and  becomes  unfit  for  food.  But 
by  the  use  of  some  preservatives,  such  as  benzoate  of  soda, 
the  fermentation  may  be  stopped,  and  by  adding  coloring 
matter  the  original  color  may  be  restored ;  then  the  mixture 
may  be  canned  and  sold.  To  outward  appearances  it  may 
seem  like  good  clean  food,  while  in  reality  it  is  entirely  unfit 
to  be  eaten. 

Condemned  foods.  Unfortunately  the  marketing  of 
spoiled  foods  is  much  commoner  than  is  commonly  sus- 
pected. In  the  state  of  Missouri  during  the  year  1912,  the 
food  inspectors  condemned  and  destroyed,  as  unfit  for  use, 
the  following  foods  which  were  offered  for  sale :  20  pounds 
of  candy,  80  cans  of  unwholesome  milk,  125  pounds  of 
spoiled  beans,  134  bottles  of  olives,  135  packages  of  break- 


THE  PUBLIC  WATER,  MILK,  AND   FOOD   SUPPLY     359 

'fast  food,  316  cans  of  decaying  canned  food,  581  bottles 
of  impure  patent  medicines,  741  pounds  of  meat  and  fish, 
12,000  pounds  of  hominy,  1885  cans  of  bad  fruits  and  vegeta- 
bles, and  225,000  eggs. 

In  New  York  City  in  1907,  362,795  pounds  of  groceries 
and  canned  goods  were  destroyed  because  they  were  unfit 
for  use.  In  1902  in  the  same  city  12,000,000  pounds,  or 
6000  tons,  of  unfit  food  were  destroyed. 

The  Secretary  of  Agriculture  estimated  that  in  former 
years  the  sale  of  adulterated  food  in  the  United  States 
amounted  to  over  a  billion  dollars  ($1,175,000,000)  or  about 
15  per  cent  of  our  entire  commerce  in  foods.  Probably 
the  conditions  are  much  better  now. 


LABORATORY  EXERCISE  31 

Purpose.     To  test  foods  for  adulterants. 

Materials.  Hydrochloric  acid,  iron  alum,  formalin,  zinc, 
lead  acetate,  white  woolen  yarn,  ammonia,  iodin,  foods  to  be 
tested. 

Directions,     i .    To  test  milk  for  formalin . 

In  order  to  see  what  the  test  is,  add  a  few  drops  of  formalin-^ 
to  5  or  i o  cc.  of  milk  in  a  test  tube.  To  this  add  an  equal 
quantity  of  strong  hydrochloric  acid  and  a  piece  of  iron  alum 
about  the  size  of  a  pinhead.  Mix  the  liquids  with  a  gentle 
rotary  motion.  Place  the  tube  in  a  beaker  filled  with  boiling 
water  and  allow  to  stand  for  five  minutes.  A  purplish  color  of 
the  mixture  shows  the  presence  of  formalin.  Try  the  test 
again  without  adding  the  formalin. 

2.  To  test  meat  products  such  as  sausage  and  chopped  meat  for 
sul fides. 

Macerate  the  sample  with  water.  Pour  about  25  cc.  in  a 
flask  and  add  pure  zinc  and  about  5  cc.  of  HCL  If  sulficles 
are  present  hydrogen  sulfide  will  be  liberated.  To  test  for 
this,  dip  a  piece  of  filter  paper- into  a  solution  of  lead;  acetate 
and  suspend  it  in  the  flask.  A  black  precipitate  on  the  paper 
indicates  the  presence  of  hydrogen  sulfide. 


360  SCIENCE  OF  HOME  AND   COMMUNITY 

3.  To  test  fruit  products  such  as  jellies,  jams,  and  sirups  for  arti- 
ficial coloring  matter. 

Place  a  few  teaspoonfuls  of  the  sample  in  water  and  boil  to 
dissolve  it.  Place  in  this  liquid  a  small  woolen  cloth  or  a  few 
pieces  of  white  woolen  yarn.  Boil  for  five  to  ten  minutes, 
stirring  occasionally.  Remove  the  cloth  and  wash  in  hot  water. 
If  the  cloth  is  brightly  colored  the  presence  of  artificial  dyes  is 
shown.  Natural  colors  give  a  dull  pinkish  brown  tinge.  To 
make  the  test  more  certain,  place  the  cloth  in  a  solution  of 
dilute  ammonia  made  by  mixing  10  parts  of  water  with  I  part 
of  ammonia.  Boil  for  about  five  minutes  and  remove  the  cloth. 
The  artificial  coloring  matter  dissolves  the  ammonia.  If  this 
is  colored,  add  HC1  to  it  till  the  mixture  is  acid.  Place  in  it  a 
fresh  piece  of  white  woolen  cloth  and  boil.  Remove  and  wash 
in  water.  If  the  cloth  is  colored,  the  presence  of  artificial  dyes 
is  shown. 

4.  To  test  ground  coffee  for  adulterations. 

Place  a  few  teaspoonfuls  of  ground  coffee  in  a  beaker  half 
full  of  cold  water  and  shake  thoroughly  and  allow  to  stand. 
Most  of  the  coffee  will  float,  while  the  chicory  and  cereal  adul- 
terants sink,  coloring  the  water  with  a  brownish  tinge. 

5.  To  test  spices  for  starchy  adulterants. 

Cloves,  mustard,  and  cayenne  contain  practically  no  starch, 
so  that  the  presence  of  starch  is  proof  of  adulteration.  To  test 
for  starch  boil  in  water  for  a  few  minutes,  allow  to  cool,  and  add 
a  drop  of  iodin.  A  blue  color  indicates  the  presence  of  starch 
and  hence  of  some  adulterant. 

6.  To  test  lemon  extract. 

To  a  test  tube  nearly  filled  with  water  add  a  teaspoonful  of 
the  extract.  If  real  lemon  oil  is  present,  it  will  be  thrown  out 
of  solution  and  will  give  a  turbid  appearance  to  the  solution 
and  will  form  a  layer  on  top  of  the  water.  If  the  solution  re- 
mains clear  after  diluting  with  water,  very  little  or  no  oil  of 
lemon  is  present. 

United  States  Pure  Food  Law.  When  people  realized  the 
injury  that  was  being  done  them  through  these  impure  foods, 
they  took  steps  to  protect  themselves  by  law.  In  1906  the 


THE  PUBLIC  WATER,  MILK,  AND   FOOD   SUPPLY     361 

United  States  government  passed  what  has  been  known  as 
the  Pure  Food  Law.  This  law  does  not  forbid  the  use  of  all 
preservatives  and  coloring  matters,  but  it  requires  prepara- 
tions put  up  in  bottles,  cans,  and  other  packages,  intended 
for  interstate  shipment,  to  bear  a  label  stating  the  materials 
contained  and  the  proportions  of  each.  One  often  sees  the 
inscription  on  foods  and  drugs  "  Guaranteed  under  the  United 
States  Food  and  Drug  Act,  June  30,  1906,  Serial  No.  — ." 
This  inscription  is  often  misunderstood  to  mean  that  the 
product  has  been  examined  by  government  inspectors  and  its 
purity  and  the  correctness  of  the  label  guaranteed.  It  would 
be  a  splendid  thing  if  this  were  so,  but  it  is  not.  The  state- 
ment on  the  label  is  merely  the  guarantee  of  the  manufac- 
turer, not  of  the  government,  under  this  act. 

But  this  law  was  important  in  that  it  established  the 
principle  that  the  government  has  the  right  to  regulate  the 
manufacture  and  sale  of  foods.  It  enables  one  to  know 
what  is  inside  the  package  and  is,  of  course,  a  check  on 
many  dishonest  manufacturers.  Under  the  federal  act 
also,  arrangements  were  made  for  the  appointment  of  in- 
spectors to  examine  meat  in  certain  establishments.  This 
federal  meat  inspection  covers  only  meat  intended  for 
interstate  shipments.  State  supervision  is  needed  to  look 
after  meat  intended  for  local  consumption.  Some  steps 
have  already  been  taken  along  this  line  and  most  of  the 
states  are  passing  and  enforcing  laws  to  protect  us  from 
impure  foods. 

United  States  Division  of  Foods.  Much  of  the  credit  for 
these  investigations  into  the  purity  of  our  food  supply  is 
due  to  the  Bureau  of  Chemistry,  which  is  a  branch  of  the 
United  States  Department  of  Agriculture.  About  thirty 
years  ago,  Dr.  Wiley,  the  former  chief  of  this  bureau,  began 
an  investigation  of  food  adulteration.  Since  then  this  work 
has  grown  in  importance,  till  about  five  years  ago  this  food 
laboratory  was  made  into  a  sub-branch  of  the  Bureau  of 


362  SCIENCE  OF  HOME  AND   COMMUNITY 

Chemistry,  and  called  the  Division  of  Foods,  with  a  force  oi 
about  twenty-five  men  devoted  entirely  to  the  study  of  foods. 
The  results  of  the  investigations  made  by  the  Bureau  of 
Chemistry  have  instructed  and  awakened  the  people  of  the 
country  and  have  thus  helped  to  make  possible  the  food 
laws  which  have  been  passed. 

City  ordinances.  Many  cities  are  passing  local  ordi- 
nances affecting  the  manufacture  and  sale  of  foods,  by 
regulating  sanitary  conditions  in  the  butcher  shop  and  the 
bakeshop  where  bread  and  other  foods  are  made  or  handled, 
and  requiring  the  covering  of  fruits  and  bread  with  screens 
to  keep  off  the  flies.  It  is  desirable  to  require  that  cooked 
foods  be  kept  in  dust-proof  receptacles,  for  dust  may  be  one 
means  of  transmitting  disease  germs.  Under  ordinary  city 
conditions  many  dust  particles  fall  on  food  left  exposed. 
Culture  plates  exposed  under  a  glass  showcase  in  a  bakery 
collected  15  bacteria  in  ten  minutes,  while  one  exposed  on 
the  open  counter  collected  800  bacteria  in  the  same  length 
of  time.  A  culture  exposed  on  a  sidewalk  fruit  stand  col- 
lected 10,000  bacteria  in  ten  minutes,  nearly  700  times  as 
many  as  under  cover.  Only  those  stores  should  be  patron- 
ized which  keep  their  food  covered.  Sometimes  bread  is 
wrapped  at  the  bakery  in  paper  and  this  helps  to  keep  it 
clean.  A  bacteriologist  who  made  an  estimate  of  the  num- 
ber of  bacteria  on  a  loaf  of  bread,  found  an  average  of  7500 
bacteria  on  a  loaf  of  unwrapped  bread  and  only  585  on  a  loaf 
of  wrapped  bread. 

"  White  list."  In  some  cities  local  organizations  help 
to  raise  a  high  standard  of  cleanliness  by  keeping  a  "  white 
list."  Members  of  the  organization  visit  and  examine  the 
stores,  and  if  they  find  a  store  clean  and  sanitary  it  is  put 
on  the  "  white  list."  If  it  is  not  clean  it  is  not  put  on  this 
list.  This  stimulates  the  storekeepers  to  make  greater 
efforts  to  keep  their  stores  clean  in  order  that  they  may  be 
advertised  as  on  the  approved  list. 


THE  PUBLIC  WATER,  MILK,  AND   FOOD   SUPPLY     363 

COMMUNITY  PROJECT  i 

Purpose.  To  investigate  local  conditions  with  reference  to 
water,  milk,  and  foods. 

Directions,  i.  The  class  may  divide  itself  into  three  com- 
mittees, a  water  committee,  a  milk  committee,  and  a  food  com- 
mittee. Each  committee  will  investigate  the  local  conditions 
with  reference  to  its  topic  and  report  to  the  class.  The  water 
committee  will  collect  information  regarding  the  source  of  water 
supply,  possibility  of  contamination,  means  taken  to  purify  it  or 
to  prevent  contamination,  means  of  distribution,  cost,  measure- 
ment of  water  used,  further  steps  needed  to  protect  the  water 
supply.  If  possible  the  committee  may  visit  the  filter  plant, 
pumping  station,  or  watershed. 

2.  The  milk  committee  will   collect  information  regarding 
the  source  of  milk,  sanitation  of  dairies,  inspection  given  by 
city,    conditions   under   which   licenses   are   granted,   need  for 
further  care  on  the  part  of  the  city.     They  may  perhaps  visit 
some  of  the  dairies  and  report  on  the  conditions  found. 

3.  The  food  committee  may  investigate  the  source  of  the 
foods  used  in  town,  inspection  given   foods  by  federal,  state, 
and  local  authorities,  the  local  ordinances,  care  exercised  by 
local  dealers  in  handling  food  supply,  other  steps  that  should  be 
taken  to  further  protect  the  food  supply. 

4.  In  the  class  discussions  of  the  reports  after  information 
on   present   conditions   has   been   presented,   special   attention 
should  be  given  to  the  things  that  still  need  to  be  done  and  to 
the  ways  in  which  the  members  of  the  class  can  help  to  bring 
these  about. 

5.  It    may   be    possible    to    make    portions    of    a    sanitary 
survey  of  a  market,  a  bakery,  and  a  dairy  suggested  in  Hoag 
and  Terman's,  Health  Work  in  the  Schools,  on  pages  244  to  251. 


SUPPLEMENTARY  QUESTIONS  FOR  CLASS  DISCUSSION 

1 .  How  may  drinking  water  become  impure  ? 

2.  How  may  it  be  purified  ? 

3.  What  results  follow  from  making  the  water  supply  pure? 


364  SCIENCE  OF  HOME  AND   COMMUNITY 

4.  How  may  milk  be  a  means  of  carrying  disease  germs  ? 

5.  What  care  is  needed  to  get  pure,  clean  milk? 

6.  Which  is  the  worst  form  of  food  adulteration  from  the 
standpoint  of  health  ? 

7.  What  has  the  national  government  done  to  help  people 
get  pure  foods  ? 

8.  What  is  your  locality  doing  to  protect  its  water,  milk, 
and  food  supply  ? 

9.  What  more  should  be  done  ? 

REFERENCES 

Coleman,  The  People's  Health,  Macmillan  Co.,  New  York  City. 

Chaps.  3-5. 
Hazen,  Clean  Water  and  How  to  Get  It,  J.  Wiley  and  Sons,  New 

York  City. 
O'Shea  and  Kellogg,    Health  and  Cleanliness,   Macmillan  Co., 

New  York  City.     Chaps.  12-14. 


CHAPTER  XXIV 
CONTAGIOUS   DISEASES 

How   are   contagious  diseases  spread  and  how 
may  they  be  controlled  ? 

Bacteria  and  disease.  Bacteria  have  a  very  important 
bearing  on  health  because  of  the  part  they  play  in  causing 
a  number  of  common  diseases.  In  some  cases  the  bacterium 
which  causes  the  disease  has  been  discovered  under  the 
microscope  and  the  cause  of  the  disease  is  thus  definitely 


3 

FIG.  149.  —  Types  of  disease  bacteria :  a,  tuberculosis;  b,  diphtheria;  c,  typhoid 
fever ;    d,  vibrio  of  cholera ;    e,  anthrax ;   /,  erysipelas ;    g,  pneumonia. 

known.  It  has  been  discovered  for  diphtheria,  tuberculosis, 
typhoid  fever,  pneumonia,  cholera,  lockjaw,  whooping  cough, 
and  blood  poisoning.  There  are  other  diseases  which  are  so 
similar  to  bacterial  diseases  in  their  general  behavior  that  it 
is  generally  believed  that  they  are  caused  by  bacteria  or 
other  microorganisms,  although  the  bacterium  has  not  been 
discovered.  Of  this  nature  are  scarlet  fever,  measles,  mumps, 
and  smallpox. 

There  is  a  great  difference  in  people  as  to  their  suscepti- 
bility to  the  action  of  these  bacteria.  Several  people  ex- 
posed to  the  same  disease  may  all  take  the  bacteria  into  their 

365 


366  SCIENCE  OF  HOME  AND   COMMUNITY 

systems,  and  yet  while  one  person  becomes  sick,  others  may 
be  unaffected,  or  very  slightly  so.  One  person  may  have 
disease  germs  in  his  system  and  not  be  affected  by  them, 
while  another  person  may  receive  these  germs  from  the  first 
person  and  come  down  with  the  disease. 

Characteristics  of  bacteria.  In  order  to  understand  how 
these  parasites  cause  disease  and  what  may  be  done  to 
control  them,  we  need  to  know  something  about  their  general 
activities. 

Size.  Bacteria  are  the  smallest  living  organisms  that  have 
been  discovered  with  the  microscope.  They  vary  in  size  from 
a  ten-thousandth  to  a  hundred-thousandth  of  an  inch  in 
diameter.  There  are  probably  others  so  much  smaller  that 
they  cannot  be  seen  even  with  the  aid  of  the  microscope. 
It  would  take  about  1500  bacteria  of  average  size  placed  end 
to  end  to  reach  across  the  head  of  a  common  pin.  It  has 
been  estimated  that  a  pint  can  would  hold  over  two  hundred 
billion  bacteria.  But  although  they  are  so  extremely  small, 
these  little  plants  play  a  very  important  part  in  man's  life 
on  account  of  their  frequent  occurrence  and  power  of  rapid 
reproduction.  While  we  cannot  see  bacteria  without  the  aid 
of  the  microscope,  the  effect  of  their  action  in  masses  is 
evident  all  around  us,  as  in  the  souring  of  milk,  the  spoiling 
of  food,  and  the  decay  of  refuse  and  other  organic  matter. 

Multiplication.  The  great  abundance  of  bacteria  depends 
upon  the  remarkable  rapidity  with  which  they  grow  and 
form  new  bacteria.  Their  means  of  multiplication  is  a 
process  called  division.  A  bacterium  divides  into  two 
similar  parts,  each  part  growing  meanwhile  till  it  is  as  large 
as  the  first  bacterium.  In  a  short  time,  sometimes  in  twenty 
minutes,  these  two  divide  to  make  four ;  in  another  twenty 
minutes  these  four  divide  to  make  eight,  and  so  on,  each 
division  doubling  the  number  of  bacteria.  At  this  rate, 
the  descendants  of  a  single  bacterium  would  amount  in  ten 
hours  to  about  a  billion.  Bacteria  do  not  continue  to  grow 


CONTAGIOUS  DISEASES  367 

at  this  rate  indefinitely  because  the  limit  of  their  multiplica- 
tion is  soon  reached  through  lack  of  food  and  through  cer- 
tain conditions  unfavorable  to  growth.  But  it  is  this  tre- 
mendous power  of  multiplication  that  makes  them  such  a 
factor  in  man's  life. 

Occurrence  and  food.  Bacteria  are  found  in  a  great  variety 
of  places :  in  the  soil,  in  the  air,  in  water,  in  food,  and  in  the 
human  body.  Some  kinds  are  injurious  to  man,  but  the 
great  majority  are  beneficial  or  harmless.  Fifteen  hundred 
kinds  of  bacteria  are  known  to  science  but  only  about  fifty 
to  seventy-five  produce  disease.  Although  these  little 
organisms  are  plants,  they  contain  no  chlorophyll  and  so 
cannot  make  their  own  food.  Some  bacteria  feed  upon 
the  living  bodies  of  plants  and  animals.  These  are  called 
parasites.  Others  live  on  the  dead  bodies  of  plants  and 
animals.  They  are  called  saprophytes. 

DEMONSTRATION  29 

Purpose.  To  see  under  what  conditions  air  contains  the 
fewest  bacteria. 

Materials.    See  demonstration  27  and  read  I  under  Directions. 

Directions,  i.  Melt  as  many  tubes  of  the  medium  as  there 
are  samples  of  air  to  be  tested.  Pour  each  into  a  sterilized  petri 
dish  and  cover  at  once.  Allow  to  stand  till  the  gelatin  hardens. 

2.  Following   are  suggested  some  of  the  various  localities 
and  times  for  testing  the  air :  in  the  schoolroom  before  school, 
and  after  school;  in  the  hall  while  classes  are  passing,  and  just 
after  sweeping ;  outdoors  on  a  windy  day,  and  on  a  still  day ;  on 
a  street  that  is  much  traveled,  on  one  that  is  little  traveled. 

3.  In  each  of  the  cases  to  be  tried  remove  the  cover  from 
the  dish,  keeping  it  off  three  minutes,  then  replace. 

4.  Allow  the  dishes  to  stand  for  several  days,  —  note  the 
appearance  of  colonies.     If  possible,  count  them.     If  too  numer- 
ous for  this,  determine  the  relative  number  of  bacteria  found 
in  the  various  localities.     Or  the  experiment  may  be  tried  again 
with  a  shorter  exposure  so  as  to  reduce  the  number  of  colonies. 


368  SCIENCE  OF  HOME  AND   COMMUNITY 

Conditions  of  growth.  The  most  important  conditions 
affecting  the  growth  of  bacteria  are  temperature  and  moisture. 
For  the  majority  of  bacteria  the  most  favorable  temperature 
is  between  60  and  100  degrees.  The  effect  of  lowering  the 
temperature  is  to  lessen  their  activity  and  they  become 
dormant  near  the  freezing  point.  At  this  point  most 
kinds  are  killed,  but  some  can  withstand  freezing  for  several 
weeks  or  months.  Such  are  the  bacteria  that  cause  typhoid 
fever,  which  may  be  frozen  in  the  ice  for  two  months  during 
the  winter  and  when  the  ice  melts  some  may  renew  their 
activities.  All  bacteria,  however,  are  killed  by  boiling,  and, 
if  the  heating  is  continued  for  an  hour,  they  may  be  destroyed 
at  a  temperature  of  160  degrees.  There  is  one  form  in  which 
bacteria  exist,  known  as  spores,  the  vitality  of  which  is  not 
destroyed  by  bringing  it  to  the  boiling  point.  Under  certain 
conditions  some  bacteria  may  stop  their  activities  and  form 
themselves  into  a  spherical  mass  surrounded  by  a  thick  mem- 
brane. These  spores  are  dormant  but  are  able  to  withstand 
adverse  conditions,  such  as  excessive  drying  and  heat  which 
would  kill  bacteria  in  their  ordinary  forms.  But  while 
spores'  are  not  destroyed  by  boiling  a  short  time,  if  the  boil- 
ing is  continued  for  several  hours,  the  spores  will  be  killed. 

Two  other  conditions  favorable  to  the  growth  of  bacteria 
are  dampness  and  darkness.  They  cannot  withstand  dry- 
ing and  the  action  of  direct  sunlight,  hence  the  need  of  having 
our  houses  well  lighted  and  our  windows  unobstructed. 

Relation  to  disease .  The  bacteria  in  their  action  within  the 
body  produce  poisons,  some  of  which  are  called  toxins,  which 
are  absorbed  into  the  blood  and  carried  through  the  body, 
producing  the  ill  effects  characteristic  of  each  disease.  All  of 
these  diseases  may  be  transmitted  from  one  person  to  another ; 
some,  however,  are  more  highly  contagious  than  others.  It  is 
very  important  that  everybody  should  know  something  about 
these  diseases ;  how  they  are  caused,  how  they  may  be  carried, 
and  how  they  may  be  avoided.  Then  every  one  will  under- 


CONTAGIOUS  DISEASES  369 

stand  how  to  protect  himself  and  his  home,  and  to  cooperate 
intelligently  with  the  board  of  health  and  other  organizations 
whose  duty  it  is  to  look  after  the  public  welfare. 

In  considering  the  part  that  bacteria  play  in  disease, 
we  need  to  understand  three  things :  first,  how  the  bacteria 
leave  the  body  of  a  sick  person ;  second,  how  they  are  dis- 
tributed from  place  to  place ;  and  third,  how  they  enter  the 
system  of  a  well  person. 

How  bacteria  leave  the  body  of  a  sick  person.  The  disease 
bacteria  leave  the  body  in  the  following  ways  :  in  the  sputum, 
in  the  excreta,  in  the  urine,  and  in  eruptions  of  the  skin. 
Sometimes  patients  who  have  recovered  entirely  from  a 
contagious  disease  may  continue  to  give  off  disease  germs 
from  their  body  for  several  years,  thus  proving  a  source  of 
danger  to  the  community. 

How  bacteria  are  distributed.  The  chief  ways  by  which  these 
bacteria  are  distributed  are  by  water,  milk,  food,  flies,  and  con- 
tact. By  contact  is  meant  the  transfer  of  fresh  germs  through 
short  distances  from  patients  to  people  near.  This  may  be 
through  mouth  spray,  clothing,  eating  utensils  or  by  direct 
contact,  as  in  kissing.  One  of  the  commonest  means  of  trans- 
fer by  contact  is  by  the  hands.  These  are  carried  to  the  mouth 
many  times  during  the  day,  and  if  they  have  come  in  contact 
with  moist  germs,  these  germs  find  easy  access  to  the  mouth. 

Formerly  it  was  believed  that  the  germs  were  carried 
by  dust,  books,  letters,  and  other  articles  that  had  been 
touched  by  the  patient ;  but  to-day  modern  medicine  is 
emphasizing  especially  the  danger  of  direct  contact  with  the 
patient  through  the  hands  and  the  sputum  given  off  as  a  fine 
spray  in  coughing  and  in  conversation.  Experiments  have 
shown  that  in  ordinary  conversation  this  spray  may  be 
carried  three  or  four  feet,  and  in  coughing  ten  feet.  This  is 
believed  to  be  one  of  the  common  means  by  which  influenza 
is  carried ;  hence  the  use  of  cloth  masks. 

Since  drying  and  sunlight  soon  kill  bacteria,  it  is  not 

2B 


370 


SCIENCE  OF  HOME  AND   COMMUNITY 


believed  that  dust  is  a  very  common  means  of  carrying 
disease  germs. 

One  way  in  which  moist  sputum  may  be  carried  is  by  shoes 
and  rubbers.  These  carry  the  germs  directly  into  the  house 
on  the  carpets  and  rugs  and  may  prove  especially  dangerous 
to  babes  playing  on  the  floor. 

The  following  table  taken  from  Dr.  Hill's  The  New 
Public  Health  shows  the  most  common  routes  of  infection. 


THE  CHIEF  INFECTIOUS  DISEASES  OF  THE 
TEMPERATE  ZONE 


CLASSIFIED  BY 
THEIR  CHIEF  ROUTES  OF  INFECTION 


Typhoid  fever  (and  other  intestinal 
infections) 

Tuberculosis  (human) 

Diphtheria,  scarlet  fever,  measles, 
German  measles,  mumps,  whoop- 
ing cough,  smallpox,  chickenpox  . 

Trachoma,  cerebro-spinal  menin- 
gitis, leprosy 


Water,  food,  flies,  milk,  contact. 
Flies,  milk,  contact. 


Milk,  contact. 
Contact. 


From  this  it  will  be  seen  that  water  and  food  carry  only 
the  intestinal  infectious  diseases  and  that  flies  as  carriers 
are  limited  to  this  group  chiefly,  as  the  amount  of  tubercu- 
losis carried  by  flies  is  small.  Milk  carries  the  first  three 
groups,  while  contact  alone  carries  them  all.  In  this  chapter 
we  are  interested  chiefly  in  the  public  means  of  transfer, 
food,  water,  milk,  and  flies. 

How  bacteria  enter  the  body.  The  chief  means  by  which 
bacteria  may  enter  the  body  are  through  the  mouth  (in  the 
food  or  drink),  through  the  nostrils  and  mouth  in  breathing, 
and  through  wounds  in  the  skin.  The  first  two  are  the  most 
common  means. 

The  various  ways  in  which  these  organisms  may  leave  the 
body  of  the  patient,  how  they  may  enter  the  body  of  another 
person,  and  how  they  may  be  carried  from  one  to  the  other 
are  shown  in  the  following  table. 


CONTAGIOUS  DISEASES 
TABLE  OF  SOME  COMMON  DISEASES 


371 


DISEASE 

How  ORGANISMS  LEAVE 
THE  BODY 

How  ORGANISMS 
ARE  CARRIED 

How  ORGANISMS 
ENTER  THE  BODY 

Diphtheria  .     . 

By    coughing,    in 

Milk,  contact. 

By  breathing,  by 

sputum. 

mouth  through 

• 

food  or  drink. 

Tuberculosis 

In     sputum,     by 

Milk,      meat, 

By  breathing, 

coughing. 

flies,  contact. 

through  wound 

in  skin,  by 

mouth  through 

food  or  drink. 

Typhoid  fever  . 

In  excreta. 

Contact,  wa- 

By mouth 

ter,  ice,  flies, 

through  food 

^nilk,  food. 

or  drink. 

Pneumonia  .     . 

Coughing. 

Dust  particles 

By  breathing. 

in  air,   con- 

tact. 

Lockjaw  . 

Soil  and  dust 

Wounds  in  skin. 

particles    in 

air. 

Smallpox      .     . 

Eruption  of  skin. 

Contact,  milk. 

By        breathing, 

through  mouth 

in  drink. 

Scarlet  fever      . 

Sputum,  discharg- 

Contact, milk. 

By  breathing, 

ing     ears,     and 

through  mouth 

nose  and  throat 

in     food     and 

discharges. 

drink. 

Measles    . 

Eruption  of  skin. 

Contact,  milk. 

By        breathing, 

through  mouth 

in  drink. 

Whooping  cough 

Coughing. 

Contact,  milk. 

By        breathing, 

through  mouth 

in  drink. 

Grippe     .     .     . 

Coughing. 

Contact. 

By  breathing. 

Hydrophobia    . 

Dogs. 

By  wound. 

Infantile  paraly- 

Throat discharges, 

Contact. 

Through     mouth 

sis  . 

sputum. 

in  food  or  by 

breathing. 

Trichinosis   . 

Pork. 

Eating  pork. 

Malaria    . 

Blood. 

Mosquito. 

Injected  by  mos- 

quito. 

Bubonic  plague 

Blood. 

Fleas  on  rats. 

Flea  bites  a  per- 

son. 

Influenza 

Coughing,    sneez- 

Contact, air. 

By  breathing. 

ing. 

37 2  SCIENCE  OF  HOME  AND   COMMUNITY 

How  to  control  diseases.  The  facts  which  we  have 
learned  in  this  chapter  show  that  in  order  to  control  these 
diseases,  the  first  step  is  to  take  such  care  of  the  sick  persons 
that  they  cannot  give  the  disease  to  others.  In  some  cases 
this  means  that  these  patients  must  be  isolated  and  others 
who  may  have  been  exposed  must  be  quarantined  in  order 
to  protect  the  health  of  other  people.  But  this  alone  is  not 
sufficient,  because  people  may  have  mild  forms  of  diseases 
without  being  seriously  sick,  and  yet  give  off  disease  germs. 
Further,  as  already  explained,  some  people  may  continue  to 
give  off  germs  for  some  time  after  they  have  recovered  from 
the  disease.  So  it  is  necessary  to  guard  the  public  routes  of 
infection  by  which  the  germs  may  be  carried :  water,  milk, 
food,  and  flies.  The  methods  of  keeping  water,  milk,  and 
food  pure  have  been  explained  in  a  previous  chapter,  and 
the  methods  of  controlling  the  fly  will  be  discussed  in  a  later 
chapter. 

A  few  facts  about  the  methods  of  controlling  some  of  the 
more  common  and  dangerous  diseases  will  now  be  given,  so 
that  each  one  may  do  his  part  toward  helping  to  do  away 
with  these  diseases. 

Smallpox  and  vaccination.  It  is  a  well-known  fact  that 
after  a  person  has  recovered  from  certain  diseases,  he  is  pro- 
tected to  some  extent  from  contracting  those  same  diseases 
again.  In  some  cases  this  protection  may  be  complete  and 
last  for  years;  in  other  cases  the  protection  may  last  for 
only  a  short  time.  The  principle  involved  in  this  is  the  one 
applied  in  vaccination  as  a  protection  against  smallpox. 
This  practice  was  discovered  over  a  hundred  years  ago  by 
an  Englishman,  Dr.  Jenner.  Cows  are  subject  to  a  mild 
disease  known  as  cowpox,  which  is  somewhat  similar  to 
smallpox.  In  vaccination  there  is  injected  into  a  person's 
system  some  virus,  which  contains  the  living  active  principle 
of  cowpox.  This  is  obtained  from  calves  raised  especially  for 
this  purpose.  If  this  "  takes,"  it  causes  a  very  mild  form  of 


CONTAGIOUS   DISEASES  373 

the  illness ;  but  as  a  result  of  this,  the  person  is  protected 
from  the  dangerous  disease  of  smallpox. 

When  the  virus  that  causes  cowpox  is  injected  into  the 
blood,  the  body  makes  a  substance,  called  antibody,  which 
offsets  the  effect  of  the  poison  and  the  person  recovers. 
This  antibody,  thus  made,  remains  in  the  system  and  is 
effective  in  neutralizing  the  injurious  effects  of  any  small- 
pox microorganisms  that  may  enter  the  body.  The  time 
that  this  immunity  lasts  varies  with  different  people,  the 
average  time  being  about  seven  years,  although  some  slight 
degree  of  immunity  is  afforded  for  a  lifetime  from  a  single 
vaccination. 

'Effect  of  -vaccination  on  the  death  rate.  Epidemics  of  small- 
pox are  so  rare  in  this  country  to-day  that  people  are  apt  to 
become  careless  about  the  matter  of  vaccination,  overlooking 
the  fact  that  it  is  vaccination  which  has  made  this  freedom 
from  smallpox  epidemics  possible.  Statistics  furnish  indis- 
putable evidence  of  the  great  blessing  that  vaccination  has 
proved  to  mankind  in  saving  hundreds  of  thousands  of  lives. 

Before  the  discovery  of  vaccination,  smallpox  was  one  of 
the  most  common  diseases,  even  more  common  than  measles 
to-day.  The  great  majority  of  people  at  some  time  had  the 
disease.  In  the  city  of  Boston  in  1721,  over  one  half  the 
people  had  the  disease  and  one  thirteenth  of  the  population 
died  of  it.  Nine  years  later,  there  was  another  epidemic 
which  was  almost  as  severe.  During  the  centuries  past 
smallpox  has  been  one  of  the  greatest  scourges  throughout 
the  world,  sweeping  off  people  by  the  thousands.  It  has 
been  estimated  that  60,000,000  people  died  of  smallpox  in 
Europe  during  the  eighteenth  century. 

Now  an  epidemic  of  smallpox  is  of  very  rare  occurrence 
in  those  countries  where  vaccination  is  commonly  practiced , 
and  the  number  of  deaths  from  this  disease  is  very  small. 
Records  that  have  been  kept  of  the  deaths  from  smallpox 
show  that  on  the  average  the  percentage  of  those  who  die 


374  SCIENCE  OF  HOME  AND   COMMUNITY 

among  people  who 'have  not  been  vaccinated  is  ten  times  as 
great  as  among  those  who  have  been  vaccinated. 

In  five  European  countries  in  which  vaccination  is  com- 
pulsory, the  average  number  of  deaths  from  smallpox  per 
million  of  population  is  five ;  while  in  six  European  countries 
that  do  not  have  compulsory  vaccination,  the  average  death 
rate  is  four  hundred,  or  eighty  times  as  high. 

When  vaccination  has  been  made  compulsory  in  a  country, 
the  effect  on  the  death  rate  has  been  very  marked  at  once. 
In  1874  Germany  passed  a  compulsory  vaccination  law. 
As  a  result,  the  average  number  of  deaths  from  smallpox  for 
the  ten  years  following  was  only  two  per  100,000  population, 
while  for  the  ten  preceding  years  it  had  been  seventy-one. 
This  meant  a  yearly  saving  of  about  twenty-five  thousand 
lives,  or  of  about  two  hundred  and  fifty  thousand  for  those 
ten  years  in  that  country  alone.  During  that  same  period 
of  ten  years,  the  death  rate  in  the  neighboring  country  of 
Austria,  where  vaccination  was  not  compulsory,  was  sixty-two 
per  hundred  thousand  of  population  as  compared  with  two  in 
Germany  where  it  was  compulsory.  In  Sweden,  the  rate  of 
cases  of  smallpox  per  million  inhabitants  was  two  thousand 
before  vaccination ;  it  fell  to  five  hundred  when  it  was  made 
optional,  and  to  five  when  it  was  made  compulsory. 

Since  the  United  States  has  taken  charge  of  the  Philippine 
Islands,  vaccination  has  been  introduced  and  as  a  result  there 
has  been  a  remarkable  decrease  in  the  number  of  deaths  from 
smallpox.  In  the  year  1897  about  40,000  people  in  the  islands 
died  of  smallpox.  In  1907,  after  vaccination  had  been  intro- 
duced, there  were  only  304  deaths,  or  less  than  i  per  cent  as 
many  as  before  vaccination. 

One  sometimes  hears  objections  raised  against  compulsory 
vaccination,  because  occasionally  it  has  been  followed  by 
serious  results.  But  in  most  of  those  cases  which  have 
been  carefully  investigated,  it  was  found  that  the  ill  effects 
were  not  due  directly  to  the  vaccine,  but  to  bacteria  which 


CONTAGIOUS  DISEASES 


375 


had  entered  the  wound  as  a  result  of  some  one's  carelessness, 
either  in  the  preparation  of  the  vaccine,  or  in  the  care  of 


PRUSSIA 

With  Compulsory  Vaccination 
and   Compulsory   Re-vacci- 
nation at  the  Age  of   12. 


HOLLAND 

With  Compulsory 
Vaccination  of  Children 
before  entering  a  School. 


AUSTRIA 
Without  Compulsory 
Vaccination. 


-120 

-UO 

-100 

Be 

the 

fere 
Law- 

Bei 

the 

ore 
Law- 

-90 

-  80 

Ov 

-70 

CA 

•  OV 

-50 

-40 

After  the  Law  of  1878 

•30 

was  passed 

20 

After  the  Law  of  1874 

" 

was  passed 

s**  

-  10 

\ 

II  .,  illn.. 

L...I 

-   0 

1868-1874 
Av'ge  Yearly 
Deaths  from 
Small-Pox  in 
everylOO.OOO 
Inhabitants 

Annual  Deaths  from 
Small-  Pox  in  every 
100,000  Inhabitants 

1866-1872 

Ar'ge  Yearly 
Deaths  from 
Small-Pox  In 
every  100,000 

Inhabitants 

Annual  Deaths  from 
Small-  Pox  in  every 
100,000   Inhabitants 

2S812&  ~~~- 

Deaths  from    Annual 
Small-Pox  la    eman  l 
every  100,000    ^aUI 
Inhabitants     i00'000 

Hi! 

Deaths  from 
'ox  in  every 
Inhabitants 

FIG.  150.  —  Showing  effect  of  compulsory  vaccination  on  death  rate  from  smallpox. 

the  wound.  Such  extreme  precautions  are  now  observed  that 
the  possibility  of  danger  from  this  source  is  very  small  indeed. 
It  is  doubtless  true  to-day  that  there  is  much  less  danger  from 


376  SCIENCE  OF  HOME  AND   COMMUNITY 

smallpox  than  formerly,  as  the  result  of  general  improvement 
in  all  methods  of  sanitation.  But  still  the  fact  remains  that 
vaccination  has  been  the  chief  means  of  controlling  smallpox 
and  saving  thousands  of  lives,  and  it  still  remains  the  most 
effective  means  of  preventing  epidemics  of  smallpox. 

Diphtheria  antitoxin.  One  of  the  most  wonderful  dis- 
coveries of  recent  years  is  the  antitoxin  treatment  for  the 
cure  and  prevention  of  diphtheria.  This  remedy  was  an- 
nounced by  a  German,  Dr.  Von  Behring,  in  1890.  Horses 
are  subject  to  diphtheria,  but  it  is  seldom  fatal  with  them. 
Their  bodies  make  antitoxins  to  offset  the  effects  of  the 
toxins  produced  by  the  bacteria.  Accordingly  horses  are 
carefully  kept  for  the  special  purpose  of  making  antitoxin 
to  be  used  with  human  beings.  Strong,  healthy  horses  are 
kept  in  clean  stables  and  carefully  looked  after.  They  are 
first  injected  with  the  toxin,  but  not  the  bacteria,  which 
causes  diphtheria,  as  a  result  of  which  they  make  in  their 
bodies  antitoxin,  and  soon  recover  from  the  disease.  After 
the  horses  are  well,  blood  is  drawn  from  their  necks  in  an 
almost  painless  way,  and  in  this  blood  is  found  the  anti- 
toxin. This  is  injected  into  the  system  of  people  suffering 
from  diphtheria  and  has  the  same  effect  there  in  curing  the 
disease  as  it  did  in  the  horse.  Not  only  is  this  an  almost 
sure  cure  for  this  disease  if  it  is  taken  in  the  early  stages, 
but  it  is  also  effective  as  a  preventive  when  given  to  members 
of  the  family  who  have  been  exposed.  This  immunity, 
however,  does  not  last  long,  usually  not  more  than  four  weeks. 

The  chief  difference  between  the  principles  involved  in  vacci- 
nation for  smallpox  and  in  the  use  of  antitoxin  for  diphtheria 
is  that  in  the  former  case  the  body  makes  its  own  antibody, 
while  in  the  latter  case,  this  antibody  is  made  in  the  body  of 
the  horse  and  then  injected  into  the  human  system. 

Effect  of  treatment  on  the  death  rate.  As  a  result  of  this 
treatment,  diphtheria  has  passed  from  being  one  of  the  most 
dreaded  diseases  to  one  that  is  seldom  fatal  if  taken  in  time. 


CONTAGIOUS   DISEASES 


377 


Statistics  everywhere  show  a  remarkable  lowering  of  death 
rates  where  this  treatment  is  applied.  In  New  York  City 
before  this  method  was  used,  40  per  cent  of  those  who  had 
the  disease  died ;  now  only  8  per  cent  die. 

The  following  table  shows  the  effect  on  the  death  rate  from 
the  use  of  antitoxin. 


BEFORE  ANTI- 

AFTER ANTI- 

LOCALITY 

TOXIN  TREAT- 

TOXIN TREAT- 

MENT 

MENT 

Chicago  . 

Total   number   of   annual 

deaths     

1471 

851 

Boston    .     .     . 

Death  rate  per  10,000  .     . 

14-5 

6.5 

New  Jersey 

Death  rate  per  10,000  . 

10.5 

3-7 

Boston  hospital 

Annual    death    rate    per 

thousand  cases 

400 

70 

This  means  an  annual  saving  of  more  than  three  hundred 
lives  in  Boston  and  of  five  hundred  and  sixty-six  lives  in 
Chicago. 

LABORATORY  EXERCISE  32 

Purpose.  To  observe  the  effect  of  the  antitoxin  treatment  for 
diphtheria  on  the  death  rate  in  New  Jersey. 

DEATH  RATE  IN  NEW  JERSEY  PER  10,000 


BEFORE  TREATMENT 

AFTER  TREATMENT 

1884 

8.2 

1898 

5-25 

1885 

II.7 

1899 

4.2 

1886 

10 

1900 

4-9 

1887 

II.4 

1901 

3-5 

1888 

14-8 

1902 

3-75 

1889 

1  1.  2 

1903 

3-7 

1890 

II 

1904 

4-5 

1891 

H-75 

1905 

3-25 

1892 

n-75 

1906 

2.8 

1893 

10.9 

1907 

3 

SCIENCE   OF   HOME   AND    COMMUNITY 

Directions,  i.  Starting  with  the  third  year  of  the  first  tabb 
put  a  dot  opposite  the  death  rate  for  that  year  in  the  column  on 
this  page  with  the  figure  3  at  the  top.  To  show  how  this  is  done 
the  first  two  years  have  been  filled  out.  Do  the  same  for  the 
remaining  seven  years.  Connect  adjoining  dots  with  straight 
lines. 

2.  Begin  with  the  third  year  of  the  second  table  and  in  the 
same  way  complete  the  other  eight  years  and  connect  the  dots 
as  above. 

Figures  at  the  left  represent  the  death  rate,  those  at  the  top, 
years. 

ist  year      2d      3rd      4th      5th      6th      7th      8th      9th       loth 


3.  Reckoning  the  population  of  New  Jersey  as  two  million, 
how  many  lives  have  been  saved  during  the  last  ten  years  in 
the  state  of  New  Jersey  through  the  antitoxin  treatment? 
To  do  this,  first  find  the  average  death  rate  for  the  ten  years 
before  the  treatment  and  then  for  the  ten  years  after.  Sub- 
tract these.  The  difference'  is  the  number  of  lives  saved  annu- 
ally for  each  ten  thousand  population.  From  this  work  out 
the  total  number  saved  in  New  Jersey  during  ten  years. 

Hydrophobia.  The  treatment  of  hydrophobia  is  another 
application  of  the  discoveries  of  modern  science.  After  a 


CONTAGIOUS  DISEASES  379 

person  has  been  bitten  by  a  mad  dog,  some  time  elapses 
before  the  symptoms  of  the  disease  appear.  During  this 
period  the  person  is  inoculated  first  with  a  weakened  virus 
of  hydrophobia  which  causes  the  body  to  form  an  antibody, 
then  with  increasingly  stronger  doses  so  that  the  body 
gradually  becomes  accustomed  to  these  attacks,  until  by 
the  time  the  effects  from  the  dog  bite  would  have  been  felt 
the  body  is  able  to  overcome  them  entirely. 

Typhoid  fever.  There  are  two  diseases  of  common 
occurrence  which  are  the  cause  of  so  many  deaths  that 
special  mention  should  be  made  of  them.  They  are  typhoid 
fever  and  tuberculosis.  They  are  due  largely  to  people's 
carelessness  and  ignorance  and  hence  are  preventable  dis- 
eases. Typhoid  fever  germs  are  often  spread  through  drink- 
ing water.  These  bacteria  live  in  the  intestines  of  the  patient 
and  pass  out  from  the  intestines  in  the  excreta,  both  the 
feces  and  the  urine.  They  may  pass  directly  with  the 
sewage  into  some  stream,  or  they  may  be  deposited  on  the 
soil,  from  which  they  may  sink  down  into  the  underground 
water  and  eventually  find  their  way  into  wells.  It  fre- 
quently happens  in  the  country  that  the  well  is  located 
very  near  the  place  which  receives  the  sewage,  and  the 
bacteria  may  pass  into  the  well  to  be  taken  into  the  bodies 
of  people  who  drink  the  water. 

In  cities  which  have  a  system  of  sewers,  it  sometimes 
happens  that  the  sewers  empty  into  a  stream  from  which  a 
city  lower  down  takes  its  drinking  water.  When  typhoid  fever 
breaks  out  in  the  first  city,  the  bacteria  are  carried  to  the 
second  city,  where  another  outbreak  occurs.  It  is  seen  thus 
that  the  prevention  of  typhoid  fever  depends  largely  on  two 
things,  the  proper  disposal  of  sewage,  and  the  purification 
of  drinking  water.  Some  facts  about  the  purification  of 
water  were  given  in  a  previous  chapter. 

Recovered  patients  a  source  of  infection.  Another  con- 
sideration which  emphasizes  the  need  of  continual  care  in 


380  SCIENCE  OF  HOME  AND   COMMUNITY 

disposing  of  sewage  and  in  the  purification  of  water  is  the 
fact  that  even  after  a  patient  has  recovered  from  the  disease, 
he  may  continue  to  carry  typhoid  germs  in  his  body  for 
several  years.  These  are  given  off  in  the  excreta,  which 
may  thus  be  a  means  of  spreading  the  germs.  Thus  such  a 
person  may  be  as  dangerous  to  the  health  of  a  community 
as  are  typhoid  patients.  It  is  estimated  that  one  person  in 
every  twenty-five  who  recovers  from  the  disease  continues  to 
carry  these  germs,  sometimes  for  as  long  a  period  as  twenty 
years. 

Household  filters.  If  the  water  supply  is  suspected  of 
being  contaminated  with  typhoid  germs,  the  surest  protec- 
tion is  to  boil  for  a  half  hour  all  water  to  be  used  for  drink- 
ing purposes.  This  will  kill  all  the  germs  and  make  the 
water  safe.  The  great  majority  of  the  common  small  filters, 
which  contain  sand  and  charcoal  and  are  attached  to  the 
faucet,  are  worse  than  useless.  They  do  not  remove  the 
bacteria  from  the  water,  and  the  dirt  which  collects  becomes 
a  breeding  place  for  bacteria.  There  are,  however,  filters 
which  will  remove  the  typhoid  bacteria.  Three  types  are  on 
the  market,  the  Pasteur,  the  Berkfield,  and  the  Chamberlain 
filters,  all  of  which  embody  the  same  principle.  These  con- 
tain unglazed  porcelain  through  which  water  passes  slowly. 
Even  these  require  careful  attention  to  insure  safety.  They 
should  be  thoroughly  cleaned  every  day,  and  every  fourth 
day  should  be  boiled  five  minutes  so  as  to  kill  the  bacteria 
in  the  pores  of  the  filter. 

Ice.  It  is  possible  for  typhoid  germs  to  be  carried  even 
in  ice.  Freezing  does  not  kill  all  the  bacteria ;  some  may 
lie  dormant  for  several  months  frozen  in  the  ice,  ready  to 
renew  their  activity  when  it  melts.  Whenever  ice  is  to  be 
used  for  cooling  water,  the  cleanest  and  safest  way  is  to 
put  the  ice  around  the  receptacle  containing  the  water  in- 
stead of  directly  in  the  water. 


CONTAGIOUS   DISEASES  381 

DEMONSTRATION  30 

Purpose.     To  see  if  ice  contains  bacteria. 

Materials.  See  demonstration  27  and  read  I  under  Direc- 
tions. 

Directions.  Melt  a  piece  of  ice  in  a  sterilized  beaker.  Take 
one  cubic  centimeter  of  the  water  and  add  it  to  a  test  tube  con- 
taining melted  culture  medium.  Shake  and  pour  into  a  steril- 
ized petri  dish.  Cover.  Allow  to  stand  a  few  days  and  see 
if  any  colonies  appear. 

Disposal  of  s'ewage.  Besides  the  question  of  the  puri- 
fication of  drinking  water,  the  matter  of  the  disposal  of 
sewage  must  be  considered  in  this  connection.  The  details 
of  this  matter  in  cities  must  be  left  for  experts  to  solve. 
There  are,  however,  methods  by  which  each  city  may  dis- 
pose of  its  sewage  without  emptying  it  into  streams.  They 
may  filter  it  by  means  of  sand  beds  or  burn  it  in  cremating 
furnaces;  the  present  method  of  contaminating  our  beauti- 
ful streams  and  rivers  is  unnecessary. 

Pasteurization  of  milk.  Milk  may  be  a  means  of  carry- 
ing the  germs  of  typhoid  fever,  tuberculosis,  diphtheria,  and 
scarlet  fever.  In  large  cities  it  is  usually  impossible  to  know 
exactly  the  place  from  which  the  milk  comes,  and  when  it 
is  fed  to  children  it  is  safer  to  treat  it  in  the  home  so  as  to 
destroy  the  bacteria.  This  may  be  done  in  two  ways,  by 
boiling  or  by  pasteurization.  The  objection  '  to  boiling  is 
that  it  so  changes  the  character  of  the  milk  as  to  render  it 
more  indigestible. 

In  the  process  of  pasteurizing,  the  milk  is  not  heated  to 
so  high  a  temperature  as  the  boiling  point,  only  to  about 
1 60  degrees.  This  temperature  is  sufficient  to  kill  the 
bacteria  and  does  not  affect  the  digestibility  of  the  milk, 
and  is,  therefore,  to  be  preferred  to  boiling.  At  this  tem- 
perature the  bacteria  which  cause  milk  to  sour  are  destroyed 
also,  and  pasteurized  milk  will  keep  sweet  longer.  Pasteur- 


382  SCIENCE  OF  HOME  AND   COMMUNITY 

ization  may  be  done  in  this  simple  way.  (See  figure  146.) 
A  pail  is  partly  filled  with  boiling  water,  and  in  this  are 
placed  the  bottles  of  milk.  The  water  should  come  nearly 
to  the  tops  of  the  bottles.  The  bottles  are  allowed  to  remain 
here  about  a  half  hour  and  the  milk  should  be  stirred  occa- 
sionally. The  boiling  water  is  cooled  by  the  milk,  and  the 
amounts  of  water  and  milk  can  be  so  regulated  that  the 
final  temperature  of  milk  and  water  will  be  about  the  160 
degrees  desired.  When  the  milk  has  been  heated  enough, 
it  should  be  cooled  quickly.  This  may  be  done  by  allowing 
cold  water  to  run  into  the  pail.  Inexpensive  pasteurizing 
outfits  may  be  bought  in  the  market. 

DEMONSTRATION  31 

Purpose.  To  try  the  effect  of  pasteurization  on  the  keeping 
quality  of  milk. 

Materials.     Beaker,  test  tubes,  thermometers. 

Directions.  Fill  the  beaker  half  full  of  water,  and  the  test 
tube  half  full  of  milk.  Put  the  test  tube  in  the  beaker.  Heat 
the  beaker  and  put  the  thermometer  in  the  water.  Regulate 
the  flame  so  as  to  keep  the  temperature  between  160  and  170 
degrees  for  about  a  half  hour.  Take  out  the  tube  and  plug 
the  mouth  with  cotton  batting.  Fill  another  tube  half  full  of 
milk  and  plug  with  cotton.  Allow  the  two  tubes  to  stand  side 
by  side  for  several  days  and  notice  how  long  the  milk  in  each 
keeps  sweet. 

Food.  Three  common  ways  in  which  typhoid  fever  germs 
may  be  carried  have  been  explained,  namely  by  water,  milk, 
and  flies.  In  addition  to  these  means  the  germs  may  some- 
times be  carried  in  various  articles  of  food,  as  on  uncooked 
fruits  and  vegetables  and  on  raw  oysters.  Epidemics  of 
typhoid  have  occurred  from  eating  uncooked  oysters,  which, 
it  was  later  found,  had  been  fattened  in  a  bay  into  which 
had  emptied  the  sewage  from  a  house  containing  a  typhoid 
patient.  A  wise  precaution  in  the  use  of  fruits  and  vegeta- 


CONTAGIOUS  DISEASES  383 

bles  is  to  wash  them  thoroughly  before  eating,  and  in  the 
case  of  oysters  to  cook  them. 

Vaccination  for  typhoid  fever.  Modern  science  has  found  a 
means  of  preventing  typhoid  fever  through  vaccination. 
In  times  of  war,  typhoid  has  always  been  the  scourge  of 
armies.  In  the  Spanish-American  War,  more  soldiers  died 
from  this  disease  than  were  killed  in  battle.  This  idea  of 
vaccination  originated  with  Professor  Wright  in  England, 
and  was  first  tried  on  a  large  scale  in  the  British  army.  As  a 
result  of  these  tests,  it  was  found  on  comparing  the  inocu- 
lated regiments  (about  9000  soldiers)  with  the  uninoculated 
(about  7000  soldiers)  that  there  were  about  ten  times  as 
many  cases  of  typhoid  among  the  latter  regiments  as  among 
the  former.  In  the  inoculated  regiments  there  were  no 
deaths,  while  among  the  non-inoculated  there  were  fourteen 
deaths. 

During  the  Japanese-Russian  War,  in  the  Japanese  army, 
where  vaccination  was  practiced,  there  were  practically  no 
cases  of  typhoid  fever;  while  in  the  Russian  army,  where 
this  treatment  was  not  employed,  the  efficiency  of  the  army 
was  greatly  reduced  through  the  large  number  of  cases  of 
typhoid. 

Similar  results  have  been  obtained  in  the  United  States 
armies.  Vaccination  has  now  been  made  compulsory 
throughout  the  army.  Before  this  treatment  was  given, 
there  were  1037  cases  of  typhoid  fever  and  76  deaths  during 
three  years  in  the  army  and  navy.  During  three  years  after 
vaccination  was  made  compulsory  there  were  only  50  cases 
and  5  deaths.  The  number  of  cases  was  reduced  to  one 
twentieth  and  the  number  of  deaths  to  one  fifteenth  of  what 
they  had  been  formerly. 

In  a  bulletin  issued  by  the  Department  of  Agriculture 
it  is  advised  that  well  persons  exposed  to  the  dangers  of 
field  service  be  vaccinated.  But  it  >is  not  recommended  for 
old  people,  very  young  persons,  civilians  who  live  at  home, 


384  SCIENCE  OF  HOME  AND  COMMUNITY 

and  for  people  in  ill  health.  The  need  of  applying  this  treat- 
ment as  widely  as  possible  is  evident  when  we  consider  the 
fact  that  there  are  annually  in  this  country  about  200,000 
cases  of  typhoid  fever  with  about  15,000  deaths. 

Method  of  typhoid  vaccination.  The  typhoid  bacteria 
are  first  allowed  to  develop  for  a  day  on  beef -tea  jelly  and 
are  then  killed  by  exposure  to  high  temperature.  This 
solution  is  then  injected  through  a  needle  prick  into  the  skin 
of  the  upper  arm.  Three  doses  are  given  at  intervals  of 
ten  days.  Only  slight  indisposition  generally  follows  the 
inoculation,  and  even  this  usually  disappears  inside  of  two 
days.  The  effect  of  introducing  this  vaccine  into  the  system 
is  to  increase  enormously  the  antibodies  in  the  blood,  which 
are  the  body's  means  of  combating  this  disease,  so  that 
when  living  typhoid  germs  do  enter  the  system  these  anti- 
bodies are  present  in  sufficiently  large  quantities  to  offset 
the  effects  of  the  poison  which  the  germs  produce.  This 
immunity  lasts  for  two  years  and  in  some  cases  longer. 

The  great  white  plague.  Another  disease  which  should 
be  especially  mentioned  is  tuberculosis  of  the  lungs,  or 
consumption,  as  it  is  called/  One  tenth  of  all  deaths  are 
due  to  this  disease  alone,  the  annual  number  of  deaths  in 
the  United  States  being  over  100,000.  The  number  of 
deaths  from  this  one  disease  equals  the  total  number  caused 
by  the  following  eight  diseases  combined :  smallpox,  typhoid 
fever,  scarlet  fever,  diphtheria,  cancer,  diabetes,  appendicitis, 
and  meningitis.  The  number  of  people  in  the  United  States 
constantly  suffering  from  consumption  is  about  500,000.  If 
the  present  death  rate  continues,  5,000,000  people  of  those 
now  living  in  this  country  will  die  of  this  disease. 

These  figures  have  been  given  so  as  to  emphasize  the  next 
statement,  that  most  of  this  terrible  loss  of  life  is  unnecessary, 
because  tuberculosis  is  a  curable  and  preventable  disease. 
As  one  looks  back  over  the  past  it  is  a  sad  thing  to  think  that 
most  of  those  thousands  of  deaths  might  have  been  pre- 


CONTAGIOUS  DISEASES 


385 


vented,  but  on  the  other  hand  as  one  looks  forward  to  the 
future,  it  is  encouraging  to  think  that  this  mortality  may  be 
very  largely  reduced  through  the  spread  of  the  knowledge 
of  how  consumption  may  be  cured  and  prevented.  It  is 
the  purpose  of  the  next  few  pages  to  give  some  of  the  in- 
formation which  one  needs  in  order  to  enable  him  to  act  his 


The  closed  window. 


Overwork. 


Crowded  rooms.  Mouth  breathing. 

FIG.  151.  —  Allies  of  consumption. 

part  as  an  intelligent  citizen  in  the  widespread  movement 
to  stamp  out  this  disease. 

How  bacteria  leave  and  enter  the  body.  Tuberculosis  of 
the  lungs  is  caused  by  bacteria  which  live  in  the  lungs,  and 
cause  little  rounded  bodies  known  as  tubercles.  The  bac- 
teria are  passing  constantly  into  the  saliva  of  the  patient 
and  leave  the  body  in  the  sputum.  While  the  chief  way 
in  which  they  are  thrown  out  is  in  the  act  of  expectora- 
tion, they  may  also  be  thrown  off  in  the  mouth  spray  in  the 

2C 


386 


SCIENCE  OF  HOME  AND   COMMUNITY 


acts  of  coughing  and  sneezing.  These  may  find  entrance 
into  another  body  in  three  ways:  (i)  by  being  breathed  in 
through  the  mouth  or  nostrils,  (2)  by  being  taken  in  food  or 
drink,  and  (3)  by  entering  wounds.  The  first  two  are  the 
most  common. 

Bacteria  in  foods.  It  is  known  that  cattle  are  subject  to 
tuberculosis  and  it  seems  now  to  have  been  definitely  proven 
that  through  the  meat  and  milk  of  diseased  cows  the  bac- 
teria of  tuberculosis  may  be  taken  into  the  human  system. 
On  the  other  hand,  cattle  may  take  the  disease  from  human 
beings  by  eating  grass  upon  which  the  sputum  of  a  sick 
person  has  been  deposited. 


FIG.  152.  —  How  the  germs  of  consumption  are  carried  from  the  sick  to  the  well. 
By  sputum.  By  two  people  taking  a  bite  from  the  same  apple. 

It  has  been  found  that  young  children  are  specially  sus- 
ceptible to  the  germs  in  milk  from  tuberculous  cows.  These 
bacteria  may  be  found  not  only  in  the  milk  itself  but  in  the 
products  obtained  from  it,  as  cream,  butter,  and  cheese  ;  and 
in  oleomargarine,  sometimes  used  as  a  substitute  for  butter. 
Investigations  made  in  the  city  of  Washington  showed  that 
5-J-  per  cent  of  the  samples  of  milk  tested  contained  bacteria 
of  tuberculosis.  It  was  found  also  that  17  per  cent  of  the 
cows  examined  in  the  neighborhood  of  this  city  were  affected 
with  tuberculosis.  Investigations  made  in  Europe  indicate 
that  the  per  cent  of  butter  containing  the  tubercle  bacilli  is 
slightly  larger  than  the  per  cent  of  milk. 


CONTAGIOUS  DISEASES 


Public  drinking  cups.  The  public  drinking  cup  is  another 
means  of  spreading  the  disease.  Tuberculous  people  use 
these  cups,  and  in  the  saliva  left  on  the  edge  are  thousands 
of  the  bacteria,  which  are  taken  into  the  mouth  of  the  next 
person  using  the  cup. 

Cure  of  tuberculosis.  The  cure  of  tuberculosis  consists 
in  the  employment  of  three  things  :  fresh  air  (night  and  day) , 


Good  food.  Rest. 

FIG.  153.  — Helps  in  the  cure  of  consumption. 

plenty  of  good,  nourishing  food,  and  rest.  All  medicines  ad- 
vertised as  cures  for  this  disease  are  useless  and  worse  than 
useless,  even  when  they  are  not  actually  harmful.  It  is  not 
necessary  for  one  to  go  to  any  particular  climate,  the  essential 
thing  being  a  location  where  a  constant  supply  of  pure,  fresh 
air  may  be  obtained. 

Window  tent.  The  window  tent  is  an  excellent  device  for 
use  in  winter  to  secure  fresh  air  without  cooling  the  room 
in  which  the  patient  is  sleeping.  This  is  simply  a  frame 
covered  with  canvas,  resting  on  the  head  of  the  bed  and  so 


388  SCIENCE  OF  HOME  AND   COMMUNITY 

fastened  to  the  window  that  little  air  can  enter  the  room. 
In  the  lower  part  is  an  opening  through  which  the  head  may 
pass  into  the  inclosure  which  receives  the  air  through  the 
window.  By  this  means  the  sleeper  obtains  a  constant  supply 
of  fresh  air  for  breathing,  while  his  body  is  not  cooled  thereby. 
A  serviceable  home-made  tent  may  be  constructed  out  of 
stiff  wire  and  canvas.  This  need  be  used  only  in  the  colder 
months,  as  at  other  times  the  windows  can  be  kept  wide 
open  without  any  discomfort. 

Prevention  of  tuberculosis.  Care  of  sputum.  The  pre- 
vention of  tuberculosis  must  look  in  the  first  place  to  the 
proper  supervision  of  those  who  already  have  the  disease. 
As  the  sputum  of  these  patients  is  the  chief  means  by  which 
the  disease  is  spread,  the  first  care  must  be  the  proper  dis- 
posal of  this  sputum.  This  should  be  deposited  either  in 
paper  napkins,  which  should  be  burned,  or  else  in  covered 
metal  cups  which  contain  some  chemical  to  kill  bacteria. 
The  bacteria  are  not  carried  in  the  breath  of  the  patient. 
A  careful  patient  is  not  dangerous  to  those  with  whom  he 
associates.  A  tuberculous  person  should  never  expectorate 
in  public  places,  where  the  sputum  may  become  a  source  of 
danger  to  the  public.  As  people  often  have  the  disease 
and  do  not  know  it,  the  general  rule  should  be  followed  by 
every  one  not  to  expectorate  in  public  places.  The  signs 
so  frequently  seen  prohibiting  expectoration  are  designed  to 
prevent  the  transmission  of  tuberculosis  through  the  ex- 
pectoration of  careless  and  thoughtless  persons. 

Protection  of  food.  The  bacteria  in  meat  may  be  killed 
by  a  thorough  cooking.  Those  in  milk  may  be  destroyed 
by  pasteurizing  as  previously  described  on  page  382.  The 
presence  of  tuberculosis  in  cattle  may  be  detected  by  what 
is  known  as  the  tuberculin  test.  There  are  laws  regulating 
to  some  extent  the  kind  of  cattle  that  may  be  kept  by  dairy- 
men, and  sold  as  meat,  and  where  these  laws  are  rigidly  en- 
forced, the  public  is  partially  protected  against  this  danger. 


CONTAGIOUS  DISEASES 


389 


Drinking  cups.  The  public  drinking  cup  should  every- 
where be  abolished.  Recently  there  has  been  invented  a 
slot  machine  so  constructed  that  if  a  penny  is  put  into  the 
slot,  there  drops  out  a  clean  cup  made  of  waxed  paper.  In 
most  schools  sanitary  drinking  fountains  are  being  used. 

Antituberculosis  movement.  In  recent  years  people  have 
become  so  awakened  to  the  fact  that  tuberculosis  is  our 
most  fatal  disease,  and  yet  that  it  is  curable  and  preventable, 


piece 

of 

paper 
7  inchee 
square. 


Fold 
D    to 
the  point 
F  on  the  line  A— C. 


E,  over  P. 


E — F,  and    there's 
your    sanitary 

DRINKING  CUR 


FIG.  154.  —  How  to  make  a  drinking  cup. 

that  organizations  have  been  formed  throughout  the  world 
for  the  purpose  of  combating  this  disease.  In  this  country 
there  are  at  least  sixty  city  committees  devoted  to  this 
purpose,  and  fifteen  state  organizations ;  and  a  few  years 
ago  there  was  formed  the  American  National  Association 
for  the  Study  and  Prevention  of  Tuberculosis.  The  various 
nations  have  organized  an  International  Tuberculosis  Con- 
gress. These  organizations  are  doing  much  in  educating 
the  people  by  means  of  exhibitions  and  the  distribution  of 
printed  matter. 


39° 


SCIENCE   OF  HOME  AND    COMMUNITY 


Sanatoriums .  Many  states  and  cities  have  instituted 
sanatoriums  where  treatment  may  be  given  to  consumptives. 
Some  large  organizations  and  private  companies  have 
planned  sanatoriums  for  the  benefit  of  the  members  and 
employees.  Frequently  neighboring  counties  unite  in  build- 
ing a  sanatorium. 

Decrease  in  the  death  rate.  Already  statistics  show  a 
steady  decrease  in  the  number  of  deaths  caused  by  tuber- 
culosis. Since  1880  the  death  rate  in  the  United  States  has 
fallen  more  than  50  per  cent. 

Year 

1900  1901  1902  1903  1904  1905  1906  1907  1908  1909  1910  1911 1912  1913  1914  1915  1916 
210 


1900  1901  1902  1903  1904  1905  1906  1907  1908  1909  1910  19111912  1813  1914  1915  1916 

Year 

FIG.  155.  —  Death  rates  from  important  causes  of  death. 


CONTAGIOUS  DISEASES 


391 


LABORATORY  EXERCISE  33 

Purpose.     To  compare  the  death  rates  for  various  diseases. 
Materials.     Figures  150  and  155. 

Directions,      i.  In  figure  155  notice  which  three  diseases  cause 
the  greatest  number  of  deaths.     Which  five  the  least. 
2.   Make  a  table  like  the  following  in  your  notebook. 


DISEASE 

DEATH  RATE 

NUMBER  WHO  DEE 

PER  CENT  OF  IN- 
CREASE OR  DECREASE 
SINCE  1900 

- 

Fill  in  the  figures  for  the  first  three  columns  for  each  disease  for 
1916,  counting  the  population  of  the  United  States  as  100,000,000. 
Put  first  the  disease  with  the  highest  death  rate  and  arrange  the 
rest  in  order. 

3.  Beginning  with  diseases  having  the  lowest  death  rate,  add 
together  the  number  of  people  killed  till  you  get  a  total  equal  to 
the  number  killed  by  tuberculosis  alone.     How  many  and  what 
diseases  does  it  take  to  do  this  ? 

4.  For  which  diseases  has  the  death  rate  been  decreasing  ?     For 
which  increasing  ?     Compare  1916  with  1900  and  work  out  for  each 
disease  the  per  cent  of  increase  or  decrease.     Put  the  figures  in  the 
fourth  column  of  the  table  above. 

Are  the  diseases  that  are  decreasing  contagious  or  organic 
diseases  ?  Which  are  those  that  are  decreasing  ?  See  if  you  can 
find  out,  either  by  using  books  or  by  asking  a  physician,  why  there 
have  been  these  changes. 

5.  Study  figure  150  to  notice  the  effect  of  vaccination  on  the 
death  rate  from  smallpox.      What  does  the  figure  show  (a)  for 
Prussia,  (b)  for  Holland,  (c)  for  Austria  ? 

6.  In  Prussia  what  was  the  average  annual  death  rate  for  the 
six  years  before  vaccination  was  made  compulsory?     What  was 
it  for  the  six  years  after  ?     The  population  of  Prussia  for  1880  was 
27,000,000.     Compute  the  number  of  lives  saved  in  this  country 


392  SCIENCE  OF  HOME  AND   COMMUNITY 

through  vaccination  from  the  years  1875  to  1886,  taking  the  above 
figure  as  the  average  population  for  these  years. 

7.  Do  the   same  for  Holland,  whose  population  in   1880  was 
nearly  4,000,000. 

8.  Estimate  the  number  of  lives  that  might  have  been  saved  in 
Austria  from  the  years  1875  to  1884  if  vaccination  had  been  made 
compulsory  as  it  was  in  Prussia.     To  do  this  first  find  the  average 
annual  death  rate  in  Austria  for  the  years  1875  to  1884.     Subtract 
from  this  the  average  annual  death  rate  in  Prussia  for  the  same  years. 
What  does  this  difference  represent  ?    The  population  of  Austria  in 
1880  was  about  22,000,000.     Remembering  that  the  death  rate 
means  the  number  of  deaths  per  100,000  inhabitants,  estimate  the 
number  of  lives  that  might  have  been  saved  by  vaccination  during 
the  years  1875  to  1884,  taking  the  above  figure  as  the  average 
population. 

COMMUNITY  PROJECT  2 

Purpose.  To  study  the  death  rate  in  your  own  state  and 
locality  for  different  diseases. 

Directions,  i.  Secure  the  latest  report  of  the  state  board 
of  health.  From  a  study  of  the  statistics  of  deaths  compute  the 
per  cent  of  deaths  from  the  ten  most  common  diseases.  Arrange 
these  in  the  order  of  the  per  cent  of  deaths. 

2.  Obtain  the  reports  from  the  city  health  officer  of  the  deaths 
in  your  city  or  county  and  work  out  the  per  cent  of  deaths  from 
the  ten  most  common  diseases. 

3.  If  possible  get  the  figures  from  some  neighboring  city  and 
compare  the  two. 

SUPPLEMENTARY  QUESTIONS  FOR  CLASS  DISCUSSION 

1.  How  can  such  small  organisms  as  bacteria  have  so  much 
influence  on  human  life  ? 

2.  What  is  the  relation  of  temperature  and  moisture  to  the 
growth  of  bacteria  ? 

3.  What   are   the   chief   means    by   which   disease   bacteria 
leave  the  body  ? 

4.  How  may  they  enter  the  bodv  ? 


CONTAGIOUS  DISEASES  393 

5.  What  are  the  chief  means  by  which  disease  bacteria  are 
carried  from  one  person  to  another  ? 

6.  How  does  the  treatment  for  diphtheria  differ  from  that  for 
smallpox  ? 

7.  What  are  the  evidences  of  the  effectiveness  of  vaccina- 
tion for  smallpox  and  of  the  antitoxin  treatment  for  diphtheria  ? 

8.  When  is  compulsory  vaccination  advisable? 

9.  What  are  the  chief  things  to  do  in  order  to  be  protected 
from  typhoid  fever  ? 

10.  Compare  vaccination  for  typhoid  fever  with  vaccination 
for  smallpox. 

1 1 .  Where  should  the  chief  emphasis  be  laid  in  the  control  of 
contagious  diseases? 

12.  What  are  the  chief  things  to  be  done  in  the  control  of 
tuberculosis  ? 

13.  What  can  you  do  to  help  in  the  fight  against  contagious 
diseases  ? 

REFERENCES 

Hough  and  Sedgwick,   The  Human  Mechanism,  Ginn  and  Co., 

Boston.     Chaps.  30-31. 
Ritchie,   Primer  of  Sanitation,  World  Book  Co.,  Yonkers-on- 

Hudson,  N.  Y. 


CHAPTER  XXV 
INSECTS  AND   DISEASES 

How  do  the  fly  and  mosquito  differ  as  regards 
(a)  the  harm  done,  (6)  their  life  history,  and  (c)  the 
means  to  be  used  to  control  them  ? 

It  has  been  proved  conclusively  within  recent  years  that 
certain  insects  are  responsible  for  much  sickness  and  many 
deaths  because  they  carry  the  organisms  which  cause  dis- 
eases. Mosquitoes  are  known  to  carry  malaria  and  yellow 
fever  and  this  is  the  only  method  by  which  these  diseases 
are  carried.  It  is  known  that  house  flies  are  one  means  of 
carrying  typhoid  fever,  Asiatic  cholera,  dysentery,  infantile 
diarrhea,  and  tuberculosis  ;  and  there  is  strong  evidence  that 
they  may  carry  also  smallpox,  ophthalmia,  and  parasitic 
worms. 

While  mosquitoes  and  flies  are  the  most  dangerous  in- 
sects as  disease  carriers  in  this  country,  there  are  other  insects 
which  carry  disease.  The  "  spotted  "  fever  of  the  Rocky 
Mountain  region  is  carried  by  a  certain  tick ;  pink  eye  in 
the  southern  states  is  carried  by  a  small  fly;  the  sleeping 
sickness  in  Africa  is  transmitted  by  flies ;  the  bedbug  may 
.  aid  in  the  dissemination  of  disease ;  fleas  found  on  rats  are 
the  means  of  spreading  bubonic  plague ;  and  several  diseases 
of  domesticated  animals  are  caused  by  insects. 

i.   HARM  DONE  BY  MOSQUITOES 

Mosquitoes  and  Malaria.  Malaria  is  caused  by  a  micro- 
scopic animal  which  lives  in  the  blood.  These  parasites 

394 


INSECTS  AND   DISEASES  395 

enter  the  red  blood  corpuscles  and  grow  till  they  occupy 
nearly  the  whole  space,  and  then  divide  into  a  number  of 
little  spores,  which,  as  the  wall  of  the  corpuscle  bursts,  pass 
out  into  the  blood.  It  is  at  this  stage  that  the  chills  which 
characterize  malaria  occur.  These  spores  enter  other  cor- 
puscles and  the  process  is  repeated. 

Some  of  these  spores  undergo  a  different  kind  of  develop- 
ment. When  these  are  sucked  up  with  the  blood  by  a 
malarial  mosquito,  they  pass  through  certain  stages  of  de- 
velopment in  the  body  of  the  mosquito,  and  at  the  end  of  a 
little  more  than  a  week  produce  spores  of  another  kind,  some 
of  which  find  their  way  into  the  salivary  glands.  When  the 
insect  bites  a  person,  these  spores  are  introduced  into  the 
blood  of  this  person  together  with  the  fluid  from  the  salivary 
glands,  and  begin  the  process  of  growth  which  brings  on 
malaria.  Thus  it  is  seen  that  the  relation  of  the  parasite 
to  the  mosquito  and  human  beings  is  a  very  vital  one.  It 
cannot  undergo  its  complete  development  in  either  one  alone, 
so  that  for  the  continuation  of  the  disease  both  human  beings 
and  this  mosquito  are  essential,  one  of  which  must  be  in- 
fected with  the  parasite. 

It  has  been  estimated  that  the  annual  financial  loss  in 
this  country  due  to  the  agency  of  mosquitoes  in  carrying 
malaria  is  $100,000,000.  The  United  States  Department  of 
Agriculture  has  made  a  study  of  the  economic  loss  sustained 
on  the  southern  plantations  on  account  of  the  sickness  and 
deaths  due  to  malaria.  These  losses  are  of  two  kinds,  those 
due  to  loss  in  time  and  those  due  to  reduced  efficiency,  at 
the  season  of  the  year  when  labor  is  most  needed  to  work 
and  harvest  the  crops.  On  one  plantation  it  was  estimated 
that  $6500  was  lost  in  one  year,  $2200  from  actual  sickness 
and  $4300  from  inefficiency  due  to  malaria. 

In  1916,  the  death  rate  per  100,000  in  the  United  States 
was  3.  This  means  that  about  3000  people  died  that  year 
of  malaria.  These  deaths  are  all  due  indirectly  to  mosqui- 


396 


SCIENCE   OF   HOME   AND    COMMUNITY 


Ked 
Corpuso/e 


A         De  ve/opmen  t 
/'n  human  b/ood. 


Thansmittedi 
by  bite  of  r 
mosqu/to.  I 


G 

Taken  in  by 
when  it  bites. 


In  sat/vary  g/and 


of  mosquito. 

Sexual  forms 


.0 


K     M  w    Sporozoites  /n 
v    A        N  mosfju/to's  body. 


in  mosquito's 
stomach. 


*^e 
Fertilized  ce//. 


FIG.  156.  —  Life  history  of  the  malarial  parasite  in  man  and  mosquito,     i,  2,  3, 
parasites  on  outer  wall  of  mosquito's  stomach. 


INSECTS  AND  DISEASES  397 

toes,  for  without  their  agency  the  disease  would  not  spread 
from  person  to  person. 

Yellow  fever.  Yellow  fever  is  also  carried  by  mosquitoes. 
The  cause  of  this  fever  is  believed  to  be  an  organism  some- 
what similar  to  that  which  causes  malaria.  The  method  by 
which  mosquitoes  carry  the  fever  is  similar.  During  the 
epidemic  of  1878,  there  were  twelve  thousand  deaths  from 
yellow  fever  in  the  United  States.  Since  the  part  that  the 
mosquitoes  play  in  carrying  this  disease  has  become  known, 
such  effective  measures  have  been  taken  to  control  the 
disease,  that  in  1910  there  was  only  one  death  from  yellow 
fever. 

These  diseases  are  not  carried  by  all  mosquitoes.  Malaria 
is  carried  by  only  one  genus,  Anopheles,  and  yellow  fever 
only  by  Stegomyia.  The  common  mosquito  (Culex),  usually 
found  around  our  buildings  in  the  northern  states,  does  not 
carry  either  of  these  diseases. 

Financial  loss  due  to  mosquitoes.  But  even  the  common 
mosquito  may  be  such  a  pest  as  to  cause  financial  loss. 
Where  they  are  especially  abundant,  they  cause  a  deprecia- 
tion of  the  value  of  the  real  estate  and  prevent  the  develop- 
ment of  sections  of  the  country  which  would  otherwise  be 
available  for  suburban  homes,  summer  resorts,  and  agricul- 
tural pursuits.  In  some  sections  of  southern  New  Jersey, 
herds  of  cattle  have  been  so  pestered  by  swarms  of  mos- 
quitoes that  dairying  had  to  be  abandoned. 

As  a  minor  matter,  mention  may  be  made  of  the  expense 
involved  in  providing  screens,  which  Dr.  Howard  estimates 
as  amounting  to  $10,000,000  annually. 

In  the  northern  United  States  where  malaria  seldom  occurs 
mosquitoes  are  nevertheless  a  great  pest,  as  they  drive  people 
indoors  during  the  evening  and  deprive  them  of  the  use  of 
the  outdoors  at  the  best  time  of  the  year,  so  that  even  in 
this  section  it  is  worth  while  to  make  an  effort  to  get  rid  of 
them. 


398 


SCIENCE  OF  HOME  AND   COMMUNITY 


2.   LIFE  HISTORY  OF  MOSQUITOES 

In  order  that  remedies  looking  toward  the  extermination 
of  the  mosquito  shall  be  applied  intelligently  and  success- 
fully, it  is  necessary  to  know  the  life  history  and  habits  of 
the  mosquito.  The  life  histories  of  all  kinds  of  mosquitoes 

are  quite  similar. 
The  following  expla- 
nation refers  to  the 
common  mosquito, 
Culex. 

The  mosquito  in 
its  development 
passes  through  the 
four  stages  of  egg, 
larva,  pupa,  and 
adult.  A  few  adult 
mosquitoes  pass  the 
winter  in  buildings, 
cellars,  and  other 
sheltered  localities. 
In  the  spring  the 
process  of  egg-laying 
begins,  and  eggs  may 
be  found  all  during 
the  summer  until 


Cu/ex  An  oph  e/e  s  (Ma/arie/j 

FIG.  157.  —  Life  history  of  common  mosquito 
(Culex)  at  left  and  of  malarial  mosquito  (Anoph- 
eles) at  right.  Notice  how  they  differ  in  each 
stage. 


float  upon  the  surface, 
hatch  on  the  same  day. 
upon  minute  organisms. 


the  cold  fall  days. 
They  are  laid  on 
water  in  little  boat- 
like  masses  which 

Under  favorable  conditions  these 
The  larvae  grow  rapidly,  feeding 

When  at  rest  the  larvae  hang  head 


downwards  with  the  tip  of  the  abdomen,  which  contains  the 
breathing  tube,  thrust  to  the  surface  of  the  water  where  air 


INSECTS  AND   DISEASES  399 

is  secured.  When  disturbed,  the  larvae  frequently  sink  to 
the  bottom  but  can  remain  only  a  few  minutes,  being 
obliged  to  return  to  the  surface  for  air. 

The  pupa,  into  which  the  larva  develops,  differs  notice- 
ably from  the  larva  in  form  and  possesses  two  breathing 
tubes  situated  on  the  thorax.  The  insect  now  rests  with  its 
head  uppermost.  The  pupa  is  active,  being  an  exception 
in  this  respect  to  the  general  rule  among  insects.  The 
insect  remains  in  the  pupal  stage  only  a  few  days ;  the  skin 
splits  and  the  adult  emerges,  resting  on  the  old  skin  at  the 
surface  of  the  water  until  its  wings  become  dry  and  hardened. 

Under  favorable  conditions  the  whole  life  history  may  be 
completed  in  ten  days,  one  day  in  the  egg,  seven  days  in 
the  larval  state,  and  two  in  the  pupal  state.  During  cool 
spells  of  weather  this  time  may  be  greatly  prolonged.  The 
development  of  the  malarial  mosquito  takes  from  fifteen  to 
twenty-four  days. 

Several  hundred  eggs  are  laid  in  a  single  mass  and  as  each 
may  develop  into  an  adult  in  ten  days,  it  is  clear  that  the 
possibilities  of  multiplication  are  enormous.  Professor 
Hodge  has  calculated  that  the  descendants  from  a  single 
mosquito  (on  the  supposition  that  one  half  are  females  and 
that  each  of  these  lives  and  lays  two  hundred  eggs)  might 
amount  in  one  hundred  and  eighty  days  to  a  number  repre- 
sented by  the  figure  two  followed  by  thirty-nine  ciphers. 
Of  course  this  never  actually  happens,  on  account  of  the 
insect's  enemies  and  the  lack  of  food,  but  it  suggests  the 
possibilities  of  growth. 

Breeding  places.  Mosquitoes  breed  in  a  great  variety 
of  places,  such  as  rain  barrels,  tin  cans  in  dump  heaps,  dishes, 
and  almost  any  receptacle  containing  water,  in  pools  of 
water,  in  ditches,  depressions,  footprints,  in  cesspools, 
hollows  of  trees,  sewer  catch  basins,  railroad  ditches,  swamps, 
and  woodland  pools.  In  fact  they  may  breed  in  almost  any 
stagnant  pool  of  water  that  stands  for  a  week  or  more.  They 


400 


SCIENCE   OF  HOME   AND    COMMUNITY 


may  even  breed  indoors,  in  flower  vases,  unused  water 
pitchers,  and  tanks.  They  may  come  from  deserted  cisterns 
or  from  sewer  traps  during  dry  spells  when  the  sewers  have 
not  been  flushed. 


3.   CONTROL  OF  MOSQUITO 

Natural  enemies  of  mosquitoes.     In  discussing  methods 
for  exterminating  the  mosquito,  it  is  important  to  know 

what  are  its  natural 
enemies  and  to  en- 
courage their  pres- 
ence. As  the  adults 
are  chiefly  nocturnal, 
their  chief  enemies 
will  naturally  be  those 
which  are  active  at 
night.  Among  the 
birds,  the  nighthawk 
and  whippoorwill  are 
night  feeders  and  de- 
stroy many  mosqui- 
toes. The  swallows, 
too,  although  not 


FIG.  158.  —  Rain  barrels,  breeding  places  for  mos- 
quitoes.    Should  be  kept  covered. 


nocturnal,  include 
mosquitoes  in  their 
diet.  Twenty-four  species  of  birds  have  been  known  to 
feed  upon  the  mosquito.  They  are  eaten  also  by  frogs,  toads, 
bats,  dragonflies,  and  other  insects,  and  many  are  caught  in 
spider  webs. 

The  larvae  and  pupae  have  many  enemies.  Nine  species 
of  shore  birds  are  known  to  feed  on  the  wigglers  of  mos- 
quitoes. Hundreds  of  larvae  have  been  found  in  the  stomach 
of  a  single  killdeer.  The  larvae  are  eaten  in  large  numbers 
by  fishes  and  many  water  insects. 


INSECTS  AND  DISEASES  401 

The  remedies  that  man  may  use  may  be  divided  into  two 
groups:  first,  those  directed  against  the  adult  stage,  and 
second,  those  directed  against  the  water  stages. 

Remedies  against  Adults.  Fumigants.  Against  the  adults, 
three  measures  may  be  taken :  fumigants  may  be  used  to 
kill  them ;  repellants  may  be  used  to  drive  them  away,  and 
screens  may  be  used  to  keep  them  out.  The  mosquitoes 
in  the  house  may  be  killed  by  burning  pyrethrum  powder. 
This  may  be  burned  completely  or  heated  on  a  shovel  or  tin 
pan.  During  the  process  the  windows  should  be  closed. 
The  mosquitoes  are  overcome  by  the  fumes  and  fall  to  the 
floor,  where  they  may  be  swept  up.  Burning  sulfur  is  very 
effective  and  is  often  used  in  fumigating  houses  which  may 
contain  disease-bearing  mosquitoes.  Special  caution  how- 
ever must  be  taken  in  its  use,  as  it  injures  certain  household 
goods. 

Repellants.  To  prevent  mosquitoes  from  biting,  certain 
substances  may  be  used,  the  odor  of  which  is  unpleasant 
to  mosquitoes.  The  best  of  these  repellants  is  oil  of  citron- 
ella.  This  may  be  applied  to  the  face  and  hands,  or  it  may 
be  placed  on  a  cloth  kept  near  one,  as  in  sleeping  rooms. 
When  applied  to  the  face,  care  must  be  taken  that  none 
enters  the  eye,  as  it  causes  intense  smarting.  Citronella 
may  be  used  alone  or  with  something  else.  Dr.  Howard 
considers  the  following  the  most  efficacious  mixture  that 
he  has  tried :  One  ounce  of  citronella,  one  ounce  of  spirits 
of  camphor,  and  one  half  ounce  oil  of  cedar.  The  effects 
of  the  citronella  last  about  an  hour.  To  retard  the  evapora- 
tion of  the  oil,  four  ounces  of  vaseline  may  be  mixed  with 
one  ounce  of  oil. 

One  of  the  best  remedies  for  the  irritation  produced  by 
mosquito  bites  is  moist  soap.  Other  remedies  which  have 
been  tried  and  found  efficient  are  glycerine,  ammonia,  alcohol, 
or  marking  the  puncture  with  naphthaline  moth  balls,  indigo, 
or  iodin. 

2D 


402  SCIENCE  OF  HOME  AND   COMMUNITY 

Remedies  directed  against  water  stages.  Two  kinds  of 
remedies  may  be  employed:  first,  the  preventive,  whose 
purpose  is  to  prevent  the  breeding  of  mosquitoes,  and  second, 
the  curative  remedies  whose  purpose  is  to  destroy  those 
mosquitoes  that  may  be  breeding.  The  first  remedy  is 
the  more  important  because  it  is  lasting  in  its  effects,  but  the 
second  serves  as  a  valuable  temporary  substitute. 

Preventive  remedies.  Among  the  first  class  of  remedies 
are  the  following:  In  large  marshes  draining  by  means  of 
ditching  is  effective.  Work  of  this  kind  on  the  salt  marshes 
of  California  and  New  Jersey  has  been  carried  on  over  large 
areas  with  marked  success.  Not  only  has  the  mosquito 
nuisance  been  abated  but  the  value  of  the  land  for  agricultural 
purposes  has  been  increased.  Some  ponds  may  be  drained 
and  small  woodland  pools  may  be  filled  with  soil. 

The  breeding  of  mosquitoes  in  cisterns,  tanks,  barrels, 
etc.,  may  be  easily  prevented  by  covering  them  with  mos- 
quito netting  or  boards. 

Empty  cans  and  b'ottles  that  accumulate  in  yards  or  dumps 
should  be  turned  over  so  that  they  will  not  hold  water. 
Better  still,  these  should  not  be  allowed  to  accumulate. 
There  may  be  frequent  community  house-cleanings  during 
which  the  cans  are  collected  and  buried. 

Mosquitoes  usually  travel  only  a  few  hundred  yards  or 
rods,  so  that  a  community  may  generally  find  relief  from 
the  mosquito  by  destroying  the  breeding  places  found  within 
the  immediate  vicinity.  But  there  are  a  few  species  which 
breed  on  the  coast  marshes,  as  in  New  Jersey,  that  are  borne 
inland  by  the  wind  to  a  distance  of  thirty  miles  or  more. 

Curative  remedies.  Fishes  may  be  introduced  into  ponds 
to  feed  upon  the  water  stages  of  the  mosquito.  The  swampy 
margins  should  be  deepened  to  allow  the  fishes  access  to  all 
parts. 

For  small  pools  and  ponds  kerosene  may  be  applied  to  the 
surface  at  the  rate  of  one  ounce  to  fifteen  square  feet.  This 


INSECTS  AND   DISEASES 


403 


stifles  the  larvae  and  pupae  and  also  destroys  many  of  the 
adults  which  come  to  lay  eggs.  To  be  most  effective  this 
must  be  applied  frequently,  as  the  film  is  easily  destroyed 
by  rain  or  wind. 

Successful  campaigns 
against  the  mosquito. 
Mosquitoes  can  be  con- 
trolled and  the  injury 
they  do  largely  prevented 
by  the  intelligent  cooper- 
ation of  the  people  of  a 
community.  There  are 
numerous  cases  where 
efforts  of  this  kind  have 
met  with  remarkable 
success.  Two  of  the 
most  successful  cases 
were  those  under  charge 
of  the  United  States  gov- 
ernment in  Cuba  and 
Panama.  At  the  close 
of  the  Spanish  War,  the 
American  soldiers  under 
charge  of  Colonel  Gorgas 
made  a  campaign  against 
the  mosquito  in  Havana 
and  the  immediate  vicin- 
ity. As  a  result  of  this 
work,  yellow  fever  was 
wiped  out  in  Havana  and 
the  number  of  deaths 
from  malaria  was  re- 
duced to  one  half  the 
first  year  and  to  one  FlG-  IS9> "~  Showing  death  rate  from  yellow 

fever  in  Havana  before  and  after  the  dis- 
quarter  the  Second  year,         covery  that  mosquitoes  carried  the  disease. 


Carrier  of  Yellow  Fever  Discovered 


404  SCIENCE  OF  HOME  AND   COMMUNITY 

and  there  has  been  a  constant  decrease  each  year 
since. 

Previous  to  the  digging  of  the  Panama  Canal,  Colonel 
Gorgas  was  appointed  sanitary  officer  of  the  canal  zone. 
He  employed  similar  methods  against  the  mosquito  there, 
with  the  result  that  yellow  fever  has  apparently  been  elimi- 
nated and  malaria  greatly  reduced.  This  work  had  a  very 
important  bearing  on  the  building  of  the  canal,  which  would 
undoubtedly  have  been  seriously  interfered  with  if  this  work 
of  Colonel  Gorgas  in  doing  away  with  the  mosquito  had  not 
first  been  done. 

In  San  Antonio,  Texas,  the  work  of  finding  and  destroying 
the  breeding  places  of  mosquitoes  was  taken  up  by  the  school 
children,  and  as  a  result  the  mortality  from  malaria  was 
reduced  seventy-five  per  cent  the  first  year,  and  entirely 
eliminated  the  second  year. 

In  the  town  of  Crosset,  Arkansas,  with  a  population  of  two 
thousand,  60  per  cent  of  the  time  of  the  doctors  was  taken 
up  in  treating  malaria.  During  the  year  1917  a  campaign 
against  the  mosquito  was  carried  on  costing  $2500,  or  $1.25 
per  person.  As  a  result  the  number  of  cases  of  malaria  was 
reduced  82  per  cent. 

LABORATORY  EXERCISE  34 

Purpose.  To  study  the  life  history  of  the  mosquito  and  to 
find  methods  of  destroying  it. 

Materials.  Mosquito  wigglers  in  tumblers  of  water  covered 
with  mosquito  netting,  fish,  tadpoles,  water  insects,  kerosene. 

Directions.  I.  Study  the  larva  and  note  (a)  its  method  of 
breathing,  (&)  its  method  of  moving,  (c}  position  when  at  rest. 
What  is  the  longest  time  that  a  larva  stays  away  from  the  sur- 
face? 

2.  Compare  the  pupa  with  the  larva  in  the  three  points 
given  above. 

3.  When    the    adult    emerges,    notice    its    resting    position. 
Describe  the  mouth  parts. 


INSECTS  AND   DISEASES  405 

4.  Place  a  counted  number  of  wigglers  in  a  dish  of  water 
with  a  fish.     Notice  how  long  before  they  are  all  eaten.     In 
another  dish  put  some  wigglers  with  a  tadpole  and  note  results. 
Try  various  kinds  of  water  insects  and  see  which  ones  eat  the 
wigglers. 

5.  In  another  dish  containing  larvae  and  pupae,  pour  a  few 
drops  of  kerosene  on  the  surface  of  the  water.     How  long  before 
you  note  any  results  ? 

COMMUNITY  PROJECT  3 

Purpose.  To  see  what  the  class  can  do  to  help  rid  the  locality 
of  mosquitoes. 

Directions,  i.  The  class  may  be  divided  into  groups,  each  to 
supervise  a  certain  section  of  the  city.  Aid  of  other  agencies  in 
town  such  as  newspapers;  civic  organizations,  and  health  officers 
should  be  sought  so  that  all  may  cooperate  for  the  best  results. 

2.  The  class  may  first  make  a  survey  to  see  what  breeding 
places   there   are  in  the  locality   and  which   of  them   contain 
wigglers.     A  map  should  be  made  to  show  this. 

3.  The  next  step  is  to  apply  remedies.     Is  it  feasible  to  have 
any  of  the  breeding  places  drained  or  filled?     Which  ones  can 
be  covered  ?     On  which  can  kerosene  be  used  ? 

i.   HARM  DONE  BY  FLY 

Method  of  doing  harm.  Until  recently  the  house  fly  has 
been  considered  merely  a  nuisance,  but  investigations  of 
the  past  few  years  have  proved  that  it  is  a  positive  source 
of  danger  as  a  means  of  carrying  diseases.  The  method  by 
which  it  carries  these  is  very  different,  however,  from  that 
of  the  mosquito  in  carrying  malaria  and  yellow  fever.  The 
kinds  of  diseases  usually  transmitted  by  the  flies  are  those 
which  may  be  taken  into  the  system  through  food  and  drink. 
The  fly  breeds  in  filth  and  frequents  filthy  places.  As  it 
walks  over  these  places,  there  adhere  to  its  feet  and  the  hairs 
on  its  body,  small  particles  of  filth  which  often  contain  those 
bacteria  that  cause  disease  ;  and  still  other  bacteria  may  be 


406 


SCIENCE  OF  HOME  AND   COMMUNITY 


FIG.  1 60.  —  Foot  of  fly, 
a  germ  carrier. 


sucked  up  through  its  proboscis  and  taken  into  its  digestive 

system.     The  fly  may  then  enter  our  homes  or  places  where 

food  is  sold ;  and  as  it  alights  on  the  food 

or  falls  into  the  milk,  it  leaves  some  of 

these  bacteria,  either  in  the  particles  of 

filth  that  fall  from  its  body,  or  in  the  fly 

specks  deposited.  When  the  food  is  eaten, 

these  germs  are  taken  into  the  human 

system  and  produce  disease.     Or,  again, 

the  fly  may  alight  directly  upon  the  face  and  fingers  of  human 

beings  and  leave  bacteria,  which  may  then  be  taken  into  the 

mouth.    The  evidence  which  is  being  gathered  indicates  that 

diseases  are  frequently  spread  by  flies. 

Evidence  against  the  fly.     Following  is  some  of  the  evi- 
dence that  flies  are  carriers  of  diseases. 

1.  It   is   the  habit   of 
flies  to  feed  on  filth  of  all 
kinds  in  which  bacteria 
are  abundant. 

2.  Bacteria  are  present 
in  great  numbers  on  flies. 
This  has  been  shown  by 
allowing  a  fly  to  walk  on 
a  medium  in  which  bac- 
teria   will    grow.      After 
this  had  stood  a  few  days, 
large  numbers  of  colonies 
of  bacteria  developed  in 
the  culture. 

The    bacteriologist    at 

the  Connecticut  Experiment  Station  devised  a  method  for 
estimating  the  number  of  bacteria  found  on  a  single  fly. 
Four  hundred  and  fourteen  flies  were  examined,  and  on  each 
fly  was  found  an  average  of  a  million  and  a  quarter  bacteria. 
Very  few  of  these  were  the  kind  that  produce  disease,  but 


FIG.  161.  —  Fly  tracks  on  a  culture. 


INSECTS  AND  DISEASES  407 

these  figures  show  the  enormous  possibilities  of  these  insects 
for  doing  harm  whenever  injurious  bacteria  are  exposed 
within  their  reach. 

DEMONSTRATION  32 

Purpose.     To  show  that  flies  carry  bacteria. 

Materials.     Two  petri  dishes,  two  tubes  of  culture  medium. 

Directions.  Melt  some  culture  medium  and  pour  into  a 
sterilized  petri  dish.  Cover.  When  the  medium  hardens, 
place  a  fly  under  the  cover  and  allow  it  to  walk  on  the  medium. 
Then  let  it  escape  and  cover  the  dish.  Prepare  another  dish 
of  culture  medium  and  cover,  but  do  not  allow  a  fly  to  walk 
on  it.  Allow  the  dishes  to  stand  side  by  side  for  several  days 
and  notice  any  differences. 

3.  Some  of  the  bacteria  present  on  flies  are  the  ones  which 
cause  diseases.     At  various  times  the  bacteria  which  cause 
typhoid  fever,   tuberculosis,   bubonic  plague,   and  cholera 
have  been  found  either  on  flies  or  in  fly  specks. 

4.  It  is  a  fact  only  too  well  known  that  flies  are  abundant 
in  houses  and  stores  and  that  they  frequently  alight  on  food. 

5.  Investigations  have  been  made  which  show  a  relation 
between  the  number  of  flies  and  the  number  of  deaths  caused 
by  diseases  which  may  be  carried  by  flies.     During  the  seasons 
of  1907  and  1908  a  committee  in  New  York  City  made  a 
special  study  of  the  conditions  found  in  that  city  with  ref- 
erence to  typhoid  fever  and  other  intestinal  diseases.     To 
obtain  some  idea  of  the  relative  abundance  of  flies  at  different 
times  of  the  year,  fly  traps  were  set  in  various  parts  of  the 
city,  and  the  number  of  flies  caught  each  day  was  counted. 
Statistics  were  gathered  regarding  the  number  of  deaths 
due  to  the  diseases  mentioned  above.     On  comparing  the 
records  of  the  number  of  flies  caught  with  these  statistics 
(taking  into  account  the  time  necessary  for  the  diseases  to 
develop) ,  it  was  found  that  there  were  the  most  deaths  during 
that  part  of  the  year  when  flies  were  present  in  largest  num- 


408  SCIENCE  OF  HOME  AND   COMMUNITY 

bers,  and  that  when  the  number  of  flies  decreased  on  the 
approach  of  cold  weather,  the  number  of  deaths  decreased 
also.  During  the  year  1908,  there  were  5550  deaths  due  to 
these  diseases.  The  committee  which  had  charge  of  this 
investigation  estimated  that  4272  of  these  deaths  were  due 
to  flies.  An  insect  which  is  believed  to  cause  over  four  thou- 
sand deaths  in  a  single  city  in  a  single  year  is  certainly  to  be 
considered  a  most  dangerous  animal.  The  following  quota- 
tion is  taken  from  Mr.  Jackson's  report  for  the  committee : 
"  Regarded  in  the  light  of  recent  knowledge,  the  fly  is  more 
dangerous  than  the  tiger  or  the  cobra.  Worse  than  that, 
he  is,  at  least  in  our  climate,  much  more  to  be  feared  than 
the  mosquito  and  may  easily  be  classed  the  world  over  as 
the  most  dangerous  animal  on  earth." 

6.  Epidemics  of  typhoid  fever  and  other  diseases  occur, 
which  can  easily  be  explained  on  the  supposition  that  the 
disease  was  carried  by  flies,  but  which  cannot  be  explained 
in  any  other  way. 

7.  In  the  city  of  Seattle,  Washington,  during  the  year 
1908,  when  a  special  crusade  was  waged  against  flies  by  the 
Board  of  Health,  the   death  rate   from  typhoid  fever  was 
reduced  one  half. 

Flies  and  typhoid  fever.  The  fly  is  such  a  common  carrier 
of  typhoid  fever  that  Dr.  Howard,  the  United  States  Ento- 
mologist, has  proposed  that  its  common  name  be  changed 
from  house  fly  to  typhoid  fly.  The  bacteria  which  cause 
typhoid  fever  pass  out  in  the  excretions  of  the  patient. 
Whenever  these  are  exposed  the  bacteria  may  be  carried  by 
flies  and  left  on  uncovered  food  and  dishes.  Five  thousand 
American  soldiers  died  of  typhoid  fever  during  the  Spanish- 
American  War.  It  is  now  believed  that  the  epidemic  was 
due  largely  to  flies,  which  were  thus  responsible  for  more 
deaths  than  the  Spanish  bullets. 

Flies  probably  rank  next  to  impure  milk  and  polluted  water, 
as  a  means  of  spreading  diseases.  In  those  cities  which 


INSECTS  AND  DISEASES  409 

have  a  pure  water  supply  it  is  believed  by  some  authorities 
that  flies  are  the  most  common  cause  of  transmitting  this 
disease.  One  estimate  states  that  the  annual  financial  loss 
in  this  country  due  to  typhoid  fever  is  over  $350,000,000. 
The  fly  as  one  means  of  spreading  this  disease  is  responsible 
for  a  portion  of  this  loss. 

Flies  and  tuberculosis.  Flies  may  also  serve  as  a  means 
of  spreading  tuberculosis.  The  sputum  of  patients  contains 
large  numbers  of  the  bacteria  that  cause  this  disease.  When- 
ever flies  feed  upon  this  sputum,  so  commonly  deposited 
by  careless  persons  on  streets  and  sidewalks,  the  bacteria 
may  be  carried  off  and  left  in  milk  and  on  various  articles 
of  food. 

Many  diseases  to  which  young  children  are  subject  are 
what  are  known  as  intestinal  diseases,  because  they  affect 
the  intestines.  The  bacteria  which  cause  these  diseases 
are  taken  into  the  system  through  the  food  and  drink. 
Flies  are  a  common  means  of  carrying  these  children's 
diseases. 

Great  as  is  the  harm  done  by  the  fly,  one  fact  stands  out 
prominently;  the  house  fly  can  be  controlled  and  nearly 
all  the  sickness  and  death  due  to  its  activities  can  be  pre- 
vented through  the  intelligent  cooperation  of  the  citizens 
of  any  community.  That  there  have  been  so  many  pre- 
ventable deaths  due  to  ignorance  and  carelessness  is  a  disgrace 
to  our  civilization,  but  on  the  other  hand  this  very  fact  gives 
great  hope  for  the  possibilities  of  the  future.  In  order  that 
we  may  be  able  to  apply  the  most  effective  remedies  in  the 
extermination  of  the  fly,  it  is  necessary  that  we  should  first 
understand  the  essential  facts  regarding  its  life  history  and 

habits. 

2.   LIFE  HISTORY  OF  FLY 

The  most  important  breeding  place  of  flies  is  horse  manure. 
They  breed  also  in  human  excrement  and  in  almost  any 
decomposing  animal  or  vegetable  matter.  Examination 


4io 


SCIENCE  OF  HOME  AND   COMMUNITY 


of  manure  piles  has  shown  that  on  the  average  a  pound  of 
manure  may  have  from  500  to  1000  larvae  in  it.  The  fly  in 
its  development  passes  through  the  four  stages  of  egg,  larva, 
pupa,  and  adult.  About  one  hundred  and  twenty  eggs  are 
laid  at  a  time  by  one  female  and  this  may  be  repeated  four 
times  in  a  season.  The  eggs  hatch  in  a  day  or  less;  the 
larval  state,  the  maggots,  lasts  from  five  to  six  days;  and 
the  pupal  state  from  five  to  seven  days.  Thus  the  entire 
period  of  development  takes  from  ten  to  fourteen  days, 
being  more  rapid  in  the  warmer  seasons  and  climates. 


Larva  Pupo  Adu/t 

FIG.  162.  —  Life  history  of  the  house  fly. 

The  females  begin  to  lay  eggs  in  from  ten  to  fourteen 
days  after  emerging  from  the  pupal  state.  Egg-laying  begins 
in  the  spring  and  continues  till  the  cold  days  of  autumn. 
During  this  period  it  is  possible  to  have  from  eight  to  twelve 
generations.  It  is  thus  seen  that  possibilities  of  increase 
during  a  single  season  are  enormous.  On  the  approach  of 
cold  weather  most  of  the  flies  die,  but  a  few  hibernate  for 
the  winter,  some  as  adults  in  cracks  and  crevices  of  build- 
ings and  a  few  in  the  puparium  state. 

3.   CONTROL  OF  FLY 

The  most  effective  fly  campaign  requires  the  cooperation 
of  citizens,  health  officers,  and  town  authorities.  It  is 


INSECTS  AND  DISEASES 


411 


naturally  the  duty  of  the  health  officials  to  take  charge  of 
the  work ;  the  aid  of  the  city  authorities  is  needed  to  furnish 
the  appropriation  to  carry  on  the  work;  and  the  intelligent 
cooperation  of  the  citizens  is  necessary  in  carrying  out  the 
ordinances  of  the  health  officials.  Often  the  first  steps  may 
be  taken  by  civic  organizations.  The  newspapers  have  al- 
ways proved  a  great  help  in  the  campaign  of  education  which 
is  usually  needed  to  arouse  the  citizens.  The  American 
Civics  Association  with  headquarters  in  Washington,  D.  C., 
is  ready  to  assist  any  local  organizations  in  taking  up  this 
work. 

Preventive  measures.  Remedial  measures  may  be  di- 
rected along  two  lines :  first,  to  prevent  the  breeding  of  flies ; 
and  second,  to  furnish 
protection  against  the 
flies  that  do  exist.  The 
first  might  be  called  pre- 
ventive, and  the  second, 
curative  remedies.  The 
more  important  reme- 
dies, because  the  most 
lasting,  are  those  directed 
toward  the  first  end.  As 
horse  manure  forms  the 
breeding  place  for  from 
90  to  95  per  cent  of  the 
house  flies,  the  chief 
thing  is  to  prevent  flies 
from  breeding  there. 
This  may  be  done  in 
two  ways,  by  removing 
the  manure  frequently 
and  by  keeping  the  manure  in  tight  bins  or  receptacles, 
covered  or  screened  so  the  flies  cannot  enter.  The  bin 
should  be  emptied  every  week.  For  a  single  horse,  a  barrel 


DIARRHEAL    DISEASE 

UNDER  6  YEARS 
TOTAL  DAYS  OF  SICKNESS 

Filthy  Area 
984 


"Flyless' 
Area 
273 


Total  Disease  Duration  as  an  Index 
of  Sanitation. 

U.S.  Public  Health  Service 


FIG.  163.  —  Effect  of  doing  away  with  flies  on 
prevalence  of  this  children's  disease. 


412  SCIENCE  OF  HOME  AND   COMMUNITY 

with  a  tightly  fitting  cover  serves  as  a  good  receptacle.  In 
order  that  this  method  should  be  most  effective,  it  is  neces- 
sary that  all  stables  should  take  the  same  precautions.  A 
single  manure  pile  uncared  for  will  furnish  enough  flies  to 
infest  a  whole  neighborhood,  for  flies  will  usually  travel 
about  a  quarter  of  a  mile  from  their  breeding  places.  A 
covered  bin  does  not  entirely  prevent  flies  from  breeding  in 
the  manure,  but  it  is  better  than  an  open  manure  pile. 

Health  departments.  Much  can  be  done  by  boards  of 
health  in  making  and  enforcing  ordinances  relative  to  the 
destruction  of  breeding  places.  The  health  department  of 
the  District  of  Columbia  has  issued  orders  to  the  effect  that 
all  persons  owning  a  building  where  domesticated  animals 
are  kept  shall  provide  for  the  storage  of  manure  a  bin  so 
covered  as  to  prevent  flies  from  entering ;  and  this  manure 
must  be  removed  from  the  city  twice  a  week  during  the 
summer  and  once  a  week  during  the  rest  of  the  year. 

In  the  country  and  in  towns  where  there  is  no  sewer  con- 
nection, it  is  important  that  sanitary  privies  be  used  to 
prevent  the  access  of  flies  to  human  excrement,  and  that 
the  privies  be  screened.  No  filth  of  any  kind  should  be 
allowed  to  accumulate  about  the  buildings.  Garbage  cans 
should  be  tightly  covered  and  frequently  emptied. 

Curative  measures.  Treating  manure  piles.  Although 
preventive  remedies  are  the  more  important,  until  they  are 
in  effective  operation,  much  can  be  done  through  curative 
remedies.  These  may  be  directed  along  two  lines :  first,  to 
kill  the  flies  and  the  larvae ;  and  second,  to  screen  one's  self 
and  one's  food  from  the  flies.  Numerous  experiments  have 
been  tried  in  treating  manure  piles  with  chemicals  to  kill  the 
larvae  and  pupae.  One  of  the  best  substances  is  borax.  This 
is  spread  on  the  manure  pile  as  a  powder,  and  then  the  pile  is 
sprinkled  with  water,  which  dissolves  the  borax.  This  solution 
kills  the  larvae  and  pupae.  About  a  pound  per  week  is  re- 
quired for  one  horse.  Hellebore  also  has  been  found  effective. 


INSECTS   AND   DISEASES 


413 


FIG.  164.  —  Hodge  fly  trap. 


Traps.  For  the  catching  of  adult  flies  -there  has  recently 
been  devised  by  Dr.  Hodge  a  new  kind  of  trap. 
He  lays  emphasis  on  the  fact  that  about  ten 
days  elapse  after  the 
emergence  of  the  fly  be- 
fore egg-laying  begins. 
Hence  the  most  successful 
line  of  attack  will  be  to 
catch  the  first  flies  that 
emerge  in  the  spring  be- 
fore they  lay  eggs.  Each 
fly  caught  then  eliminates 
thousands  of  flies  that 
might  have  descended 
from  this  one  during  the 
season.  The  general  plan 
of  Dr.  Hodge's  trap  is 
much  like  the  old-fash- 
ioned traps,  but  it  is  used 
in  a  different  way.  It  is 
placed  over  a  hole  in  the 
cover  of  a  garbage  can, 
the  cover  is  slightly  lifted 
so  that  the  flies  can  enter 
the  can,  then  when  they 
seek  to  escape  they  are 
caught  in  the  trap.  One 
of  these  traps  caught  2500 
flies  in  less  than  an  hour. 
The  flies  may  be  killed  by 
submerging  the  trap  in  hot 
water.  Dr.  Hodge  writes 
that  a  single  trap  has  ^o- ^5. -A  fly  trap  easily-made. 

worked  so  successfully  that  he  has  not  found  it  necessary 
to  put  up  screens  on  doors  or  windows.     This  trap  is  also- 


414  SCIENCE  OF  HOME  AND   COMMUNITY 

provided  with  a  base  in  which  bait  may  be  placed  to  attract 
the  flies,  so  that  the  trap  may  be  kept  indoors.  Bread  and 
milk  are  most  effective.  Many  kinds  of  large  traps  are  being 
used  which  have  proved  effective,  when  properly  baited  and 
located. 

Poisoning  flies.  It  is  possible  also  to  poison  flies.  One 
of  the  best  preparations  for  this  purpose  is  formalin.  The 
weak  solution  used  is  not  dangerous  to  human  beings,  but 
is  very  effective  in  poisoning  flies.  A  2  per  cent  solution 
should  be  used,  made  by  adding  two  tablespoonfuls  of  the 
solution  as  bought  at  the  drug  store  to  a  pint  of  water,  or 
water  and  milk.  It  will  prove  more  attractive  to  the  flies 
if  sugar  or  bread  and  sugar  are  added  to  it.  This  may  be 
placed  in  shallow  vessels.  A  convenient  way  of  having  a 
constant  supply  is  to  fill  a  bottle  with  the  solution,  break  a 
little  nick  in  the  top  of  the  bottle  so  that  the  liquid  can  flow 
out,  and  then  invert  it  in  a  saucer.  Flies  cannot  live  long 
without  something  to  drink  and  they  naturally  seek  liquid 
early  in  the  morning.  If  the  liquids  in  the  room  are  removed 
or  covered  up  in  the  evening,  the  formalin  will  prove  more 
effective.  Some  of  this  solution  may  be  kept  outdoors  on 
the  porch  as  well  as  indoors. 

Screens.  As  a  protection  against  the  flies  that  are  not 
killed,  the  doors  and  windows  should  be  well  screened.  A 
piece  of  sticky  flypaper  placed  on  the  outside  of  the  screen 
door  will  catch  many  flies  which  otherwise  would  enter  the 
house  when  the  door  is  opened.  . 

Protection  of  food.  All  food  when  not  in  use  upon  the 
table  should  be  screened  or  placed  where  flies  cannot  reach 
it.  Only  those  bakeries,  fruit  stands,  and  grocery  stores 
should  be  patronized  which  keep  the  food  offered  for  sale 
well  screened  from  flies.  Some  cities  have  passed  ordinances 
requiring  that  food  exposed  for  sale  shall  be  protected  from 
flies  and  dust.  The  supervision  of  this  matter  is  sometimes 
taken  over  by  civic  organizations. 


INSECTS  AND  DISEASES  415 

Fleas  and  bubonic  plague.  One  of  the  most  terrible 
scourges  recorded  in  history  is  that  of  bubonic  plague  or 
"  black  death."  This  disease  is  caused  by  bacteria  which 
attack  rats  as  well  as  human  beings.  It  has  been  shown 
that  fleas  are  the  means  of  carrying  these  bacteria  from 
rats  to  human  beings.  The  flea  sucks  the  blood  of  the  rat 
which  contains  thousands  of  bacteria ;  later  he  may  pierce  the 
skin  of  a  human  being,  thus  permitting  the  bacteria  to  enter 
that  cause  the  development  of  the  disease.  Not  long  ago 
when  the  plague  broke  out  in  San  Francisco,  it  was  success- 
fully controlled  by  waging  a  warfare  on  rats,  which  were 
indirectly  the  means  of  spreading  the  disease  through  fleas 
that  lived  upon  them.  It  was  also  found  that  ground  squirrels 
were  subject  to  the  disease  and  that  fleas  might  carry  the 
disease  from  them  as  well  as  from  rats. 

COMMUNITY  PROJECT  4 

Purpose.  To  learn  what  the  class  can  do  to  help  control  the 
fly  nuisance. 

Directions,  i.  The  campaign  may  be  started  in  the  late 
winter  or  early  spring.  Encourage  the  free  use  of  fly  traps. 
Some  members  of  the  class  may  make  fly  traps  to  sell.  Send 
five  cents  .in  stamps  to  the  International  Harvester  Company, 
Harvester  Building,  Chicago,  111.,  for  a  fly  trap  pattern.  This 
gives  detailed  directions  for  making  a  fly  trap  in  such  a  simple 
way  that  any  boy  or  girl  can  make  one. 

2.  For  fifty  cents  there  may  be  obtained  from  the  same 
company,  a  set  of  twelve  stencils,  three  feet  square,  of  the 
house  fly,  giving  drawings  that  may  be  reproduced  on  the 
blackboard,  on  paper,  or  on  cloth.  Cloth  charts  could  easily 
be  made  by  various  members  of  the  class.  There  might  be 
opportunities  to  use  these  charts  by  giving  talks  to  some  of  the 
rooms  in  the  graded  schools.  Various  members  of  the  class 
may  be  assigned  to  give  a  talk  on  the  different  charts,  which 
may  be  taken  around  to  the  rooms  to  be  visited.  The  class 
might  prepare  a  whole  evening's  entertainment  on  the  fly  to 


4l6  SCIENCE  OF  HOME  AND   COMMUNITY 

which  friends  and  parents  would  be  invited.     This  might  serve 
as  a  good  opportunity  to  organize  a  fly  prevention  campaign. 

3.  The  specific  things  that  the  class  can  do  should  be  dis- 
cussed, and  plans  made  to  put  these  into  effect.  Attention 
may  be  given  to  the  things  that  each  member  can  do  in  his  own 
home.  The  cooperation  of  all  possible  agencies  in  the  locality 
should  be  sought. 

SUPPLEMENTARY  QUESTIONS  FOR  CLASS  DISCUSSION 

1.  Which  is  the  more  dangerous  animal,  the  fly  or  the  mos- 
quito ? 

2.  What  is  the  most  conclusive  evidence  against  the  house 
fly  as  a  carrier  of  disease? 

3.  Show  why  it  is  necessary  to  understand  the  life  history 
of  the  fly  and  mosquito  in  order  to  fight  them  successfully. 

4.  What  kind  of  measures  against  the  fly  and  mosquito  re- 
quire the  cooperation  of  all  the  people  concerned  ? 

5.  What  measures  can  be  taken  by  each  individual  regard- 
less of  what  his  neighbors  may  do  ? 

6.  What  are  the  best  steps  to  be  taken  in  a  community  in  a 
campaign  against  the  fly  ?     What  against  the  mosquito  ? 

7.  Against  which  insect   can  remedies  be  more  effectively 
applied  in  the  adult  stage  ? 

REFERENCE 

Doane,   Insects  and  Disease,  Henry  Holt  and  Company,  New 
York  City. 


CHAPTER  XXVI 
HEALTH   OFFICERS 

1.  What  are  the  duties  of  health  officers? 

2.  What  sort  of  ordinances  should  a  city  pass 
in  order  to  protect  the  health  of  its  citizens  ? 

When  people  are  living  together  in  communities,  it  is 
necessary  for  all  to  cooperate  in  order  to  look  after  those 
matters  that  affect  the  public  health.  This  work  is  in- 
trusted to  a  group  of  men  called  the  board  of  health,  or  to 
one  man  called  the  health  officer. 

Amount  of  money  spent.  Our  American  towns  and  cities 
have  given  altogether  too  little  attention  and  money  to  the 
very  important  work  of  looking  after  the  health  of  the  com- 
munity. The  work  of  the  boards  of  health  is  greatly  handi- 
capped by  lack  of  funds.  An  investigation  made  of  the 
amount  of  money  spent  by  various  cities  in  maintaining 
the  work  of  the  board  of  health  showed  that  in  cities  of  from 
30,000  to  50,000  population,  an  average  of  only  twenty-seven 
cents  per  capita  was  spent  annually.  This  is  altogether 
inadequate  to  provide  for  the  maintenance  of  an  effective 
health  board;  at  least  twice  this  amount  should  be  spent. 
In  cities  of  20,000  population  and  over,  one  man  should  be 
employed  to  give  his  entire  time  to  the  work.  And  in  the 
case  of  smaller  towns,  several  towns  may  unite  to  employ 
a  man. 

Politics  and  health.  One  thing  that  greatly  hinders  the 
work  of  looking  after  the  public  health  at  the  present  time 
is  the  fact  that  the  appointment  of  the  officers  is  too  often 

2E  417 


4i8 


SCIENCE  OF  HOME  AND   COMMUNITY 


a  matter  of  politics.  Men  are  appointed  on  account  of  some 
political  pull  without  reference  to  their  fitness  for  the  work. 
The  selection  of  health  officers  should  be  taken  out  of  politics 
and  only  specially  qualified  men  should  be  appointed.  A 
board  of  health  should  have  at  least  one  physician  connected 
with  it.  It  is  desirable  that  the  health  officer  should  do  no 
practicing. 

Duties.  The  board  of  health  has  many  important  duties 
to  perform.  These  may  be  divided  into  six  groups :  first,  to 
collect  vital  statistics;  second,  to  control  communicable 
diseases;  third,  to  reduce  infant  mortality;  fourth,  to  look 
after  water,  milk,  and  food;  fifth,  to  keep  the  town  clean; 
and  sixth,  to  control  the  fly  and  mosquito  nuisances. 


St.  Paul 

Minneapolis 

Milwaukee 

Los  Angeles 

Cleveland 

Rochester 

San  Francisco 

St.  Louis 

Kansas.  City 

Detioit 

Indianapolis 

Buffalo 

Jersey  City 

Denver 

Newark 

Louisville 

Boston 

Cincinnati 

Providence 

Pittsburg 

Baltimore 

Washington,  D.C. 

New  Orleans 


214,744 
301,408 
373,857 
319,198 
560,663 
218,149 
416,912 
687,029 
248,381 
465,766 
233,650 
423,715 
267,779 
213,381 
347,469 
223,928 

670,585 
363,591 
224,326 
533,905 
558,485 
331,069 

339,075 


2558 
3739 
5205 
4538 
8047 
3215 
6319 

10888 
3966 
7452 
3824 
6940 
4401 
3533 
5784 
3756 

11562 
6319 
398o 
9603 

10753 
6511 
7250 


FIG.  166.  —  Annual  death  rate  per  1000  of  the  chief  cities  of  the  United  States. 

Vital  statistics.  The  vital  statistics  are  the  records  of 
all  the  births  and  deaths  that  occur,  of  the  causes  of  the 
deaths,  the  age  of  the  person  deceased,  and  similar  details. 
It  is  very  important  to  know  what  per  cent  of  deaths  occur 
from  each  disease  in  order  to  know  which  are  the  most 


HEALTH  OFFICERS 


419 


dangerous  diseases  against  which  special  precautions  should 
be  taken.  A  comparison  may  be  made  with  the  average 
statistics  from  other  cities ;  and  if  this  shows  that  the  death 
rate  from  some  particular  disease  is  unusually  high,  special 
attention  may  be  given  to  controlling  this  desease. 

Control  of  contagious  diseases.     One  of  the  duties  to  which 
special  attention  is  given  is  the  prevention  and  control  of 


FIG.  167.  —  Effect  of  isolation  and  disinfection  on  scarlet  fever  and  diphtheria. 

diseases  that  may  be  carried  from  one  person  to  another, 
such  as  diphtheria,  smallpox,  and  tuberculosis.  In  protect- 
ing well  people  from  unconsciously  coming  into  contact 
with  those  who  have  the  diseases,  very  strict  measures  must 
be  taken,  such  as  isolating  the  patient  and  quarantining 
people  who  have  been  exposed.  Sometimes  this  may  cause 
some  inconvenience  to  the  people  concerned,  but  it  is  neces- 


420  SCIENCE  OF  HOME  AND   COMMUNITY 

sary  in  order  to  protect  other  people.  Placards  are  placed 
on  houses  which  contain  patients  with  these  diseases,  as  a 
warning  to  other  people.  After  the  patient  has  recovered, 
sometimes  it  is  necessary  to  disinfect  the  house  to  kill  the 
bacteria  that  cause  the  disease. 

As  a  protection  against  smallpox,  compulsory  vaccination 
may  be  required  sometimes;  and  the  board  of  health  may 
furnish  free  the  virus  for  smallpox  vaccination,  the  vaccine 
for  vaccination  against  typhoid  fever,  and  the  antitoxin  for 
diphtheria. 

The  board  of  health  may  visit  the  schools  to  examine  the 
children  for  evidences  of  communicable  diseases,  and  take 
measures  to  guard  against  an  increased  number  of  cases. 


FIG.  168.  —  Antitoxin  for  diphtheria. 

School  inspection  daily  or  semi-weekly  by  a  school  nurse  is 
the  best  means  of  controlling  infectious  diseases. 

Milk  supply.  Many  of  the  deaths  among  infants  can  be 
avoided  by  furnishing  visiting  nurses  and  by  careful  in- 
spection of  milk.  One  tenth  of  the  cases  of  consumption 
among  children  are  believed  to  £ome  from  cow's  milk  that 
contains  disease  germs. 

The  milk  supply  of  a  town  should  be  carefully  inspected 
to  determine,  first,  that  it  is  free  from  disease  germs ;  second, 
that  it  is  not  adulterated;  and  third,  that  no  chemical  has 
been  added  to  prevent  it. from  souring.  The  first  is  by  far 
the  most  important.  All  persons  handling  food  or  milk 
should  be  tested  for  and  known  to  be  free  from  tuberculosis 
and  typhoid.  Cattle  should  be  tested  for  tuberculosis. 
The  dairy  farms  should  be  carefully  inspected,  and  if  the 
necessary  sanitary  conditions  are  not  found,  the  license  to 
sell  milk  should  be  taken  away  till  the  conditions  are  reme- 
died. Frequent  inspection  of  these  farms  is  necessary. 


HEALTH   OFMCERS  421 

Food  supply.  The  public  food  supply  should  also  be 
carefully  guarded.  The  places  where  the  food  is  cooked, 
the  bakeshops,  should  be  carefully  inspected.  The  room 
where  the  food  is  cooked  and  handled  should  be  kept  clean 
and  sanitary.  No  persons  having  contagious  diseases  should 
be  allowed  to  work  in  these  shops.  The  food,  when  exposed 
for  sale,  should  be  covered  to  protect  it  from  dust  and  flics. 
The  purity  of  the  food  should  .be  guaranteed  by  state  and 
national  laws. 

Butcher  establishments,  where  animals  are  killed  or  where 
meat  is  sold,  should  be  carefully  watched.  Inspectors  should 
make  sure  that  no  animal  with  tuberculosis  is  sold  for  meat 
and  that  all  meat  is  kept  under  sanitary  conditions. 

Water  supply.  The  public  water  supply  should  be  guarded 
with  special  care  to  see  that  no  disease  germs  are  allowed 
to  enter  it.  If  the  water  comes  from  lakes  and  rivers,  the 
surrounding  areas  should  be  watched  to  see  that  they  are 
not  contaminated  by  disease  germs  that  might  enter  from 
sick  people  living  near.  If  the  water  is  taken  from  a  lake 
or  river  into  which  sewage  flows,  care  should  be  taken  to  see 
that  the  inlet  for  the  water  is  located  a  long  distance  from 
the  outlet  of  the  sewer.  If  water  is  taken  from  artesian 
wells,  the  pipes  should  be  watched  to  see  that  no  leaks  allow 
disease  germs  from  the  sewer  pipe  to  enter. 

Keeping  town  clean.  It  is  usually  the  duty  of  the  board 
of  health  to  see  that  the  town  is  kept  free  from  certain 
kinds  of  filth.  Arrangements  are  usually  made  by  them  for 
the  collection  of  garbage,  ashes,  rubbish,  and  manure. 

Fly  and  mosquito  control.  Closely  allied  with  the  matter 
of  cleanliness  is  the  matter  of  fly  control.  The  board  of 
health  should  take  measures  to  see  that  the  breeding  places 
of  flies,  chief  among  them  the  manure  piles,  are  so  frequently 
removed  that  flies  have  no  opportunity  to  breed.  Ordinances 
should  be  enforced  relative  to  the  protection  of  food  from 
flies. 


422  SCIENCE  OF  HOME  AND   COMMUNITY 

In  the  southern  states,  where  malaria  and  yellow  fever  are 
found,  the  board  of  health  should  take  measures  to  control 
the  mosquito  nuisance.  Some  of  the  means  by  which  this 
may  be  done  have  been  explained  in  a  previous  chapter. 

As  an  example  of  what  is  being  done,  the  following  quota- 
tions are  taken  from  a  list  of  city  ordinances  relating  to 
public  health,  passed  in  a  city  of  10,000  population. 

PURPOSE  OP  THE  DEPARTMENT  OF  PUBLIC  HEALTH. 
"  Section  6.  The  department  of  public  health  shall  exercise 
general  supervision  over  the  health  of  the  city.  It  shall 
make  such  investigations  and  reports,  and  obey  such  direc- 
tions concerning  communicable  disease,  as  the  State  Board 
of  Health  of  the  State  of  Minnesota  may  require  or  give, 
and  under  the  general  supervision  of  the  State  Board  of 
Health,  it  shall  cause  all  laws  and  regulations  relating  to  the 
public  health  to  be  obeyed  and  enforced." 

DUTY  OF  THE  PEOPLE.  "  Section  8.  Every  person  in 

the  city  of shall  observe  and  obey  each  and  every  special 

regulation  and  every  order  of  the  department  of  public 
health  that  is  or  may  be  made  for  carrying  into  effect  any 
of  the  provisions  of  this  or  any  other  ordinance  of  said  city 
relative  to  the  health  thereof,  or  any  law  of  this  state  or 
otherwise,  whether  issued  directly  by  such  board,  or  pro- 
mulgated by  the  health  commissioner." 

DUTIES  OF  THE  HEALTH  COMMISSIONERS.  "  Section  10. 
The  health  commissioner  shall  be  president  of  the  depart- 
ment and  shall  have  and  exercise  a  general  supervision  over 
the  sanitary  conditions  of  the  city.  He  shall  give  the  council 
and  the  department  of  public  health  all  such  professional 
advice  and  information  as  they  may  require,  for  the  purpose 
of  preserving  the  public  health.  He  shall  investigate  the 
existence  of  any  communicable  or  pestilential  disease  and 
adopt  all  measures  necessary  to  arrest  the  progress  thereof." 

"  He  shall  enforce  all  laws  of  the  State,  and  ordinances  of 
the  city,  in  relation  to  health  and  sanitary  conditions,  and 


HEALTH   OFFICERS  423 

shall  cause  all  nuisances  as  hereinafter  denned  to  be  abated 
or  removed.  He  is  hereby  empowered  and  it  is  hereby  made 
his  duty  and  the  duty  of  the  health  inspectors  to  enter  any 
building  in  said  city  between  sunrise  and  sunset,  for  the 
purpose  of  ascertaining  if  such  building  is  in  good  sanitary 
condition." 

CARE  OF  FOOD.  "  Section  17.  No  food,  meat,  fish,  birds 
or  fowl  or  vegetables,  nor  any  milk,  not  being  then  healthy, 
fresh,  sound,  wholesome  and  safe  for  human  food,  nor  any 
meat  or  fish  that  died  by  disease  or  accident,  shall  be  brought 

within  the  City  of or  held  for  sale  at  any  public  or 

private  markets,  as  such  food,  anywhere  in  said  city." 

"  Section  20.  Every  person  being  the  owner,  agent, 
lessee,  or  occupant  of  any  room,  stall  or  place  where  any 
food,  meat,  fish  or  vegetables  designated  or  held  for  human 
food  shall  be  stored  or  kept  or  shall  be  held  or  offered  for 
sale,  shall  put  or  keep  such  room,  stall  and  place1  and  its 
appurtenances  in  a  cleanly  and  wholesome  condition,  and 
every  person  having  charge  (or  interested  or  engaged,  whether 
as  principal  or  agent)  in  the  care,  or  in  respect  to  the  custody 
or  sale  of  any  food,  meat,  fish,  birds,  fowls  or  vegetables 
(designated  for  human  food)  shall  put  and  preserve  the 
same  in  a  cleanly  and  wholesome  condition,  and  shall  not 
allow  the  same  or  any  part  thereof  to  be  poisoned,  infected, 
accessible  to  flies  or  rendered  unsafe  or  unwholesome  for 
human  food." 

REMOVAL  OF  MANURE.  "Section  28.  Between  the  15 th 
day  of  April  and  the  i5th  day  of  October  of  each  year,  the 
owner,  proprietor,  agent  or  occupant  of  any  stable  or  barn 
where  horses,  cows,  or  other  domestic  animals  are  kept 
within  said  city,  shall  not  deposit,  cause  to  be  deposited  or 
allow  to  accumulate  within  or  about  such  premises  for  a 
longer  time  than  twenty-four  hours,  any  manure,  animal 
bedding,  or  barn  refuse,  but  shall  provide  a  box  of  sufficient 
size  for  the  reception  of  such  manure,  animal  bedding  or 


424  SCIENCE  OF  HOME  AND   COMMUNITY 

barn  refuse,  into  which  box  shall  be  deposited  or  caused  to 
be  deposited  all  such  manure,  animal  bedding  or  barn  refuse, 
and  said  box  shall  be  so  constructed  that  the  contents  thereof 
is  not  accessible  to  flies,  and  shall  be  placed  upon  the  premises- 
owned,  occupied  or  controlled  by  such  person  in  a  situation 
as  remote  as  possible  from  any  surrounding  dwelling  or  street, 
and  shall  empty  and  cleanse  the  same  as  often  as  necessary 
and  whenever  directed  to  do  so  by  the  department  of  public 
health." 

EXPECTORATING.  "  Section  31.  No  person  shall  spitr 
or  expectorate  or  deposit  or  place  any  sputum,  spittle,  saliva, 
phlegm,  mucus,  tobacco  juice,  cigarette  stumps  or  quids 
of  tobacco  upon  the  floor  or  stairway  of  any  part  of  any  public 

hall  or  building  in  the  City  of or  upon  the  sidewalk  of 

any  public  street,  avenue  or  highway  in  the  City  of  r 

or  upon  the  floors  or  inside  furnishings  or  equipments,  or 
in  any  place  upon  the  outside  or  upon  the  platform  of  any 
street  car  while  the  same  is  in  use  upon  any  of  the  streets 

or  highways  in  the  City  of  ,  or  in  any  manner  defile 

or  pollute  the  floor,  furnishings,  equipments  or  platform  of 
any  street  car  while  in  use  upon  any  of  the  streets  or  high- 
ways of  said  city." 

FINES.  "  Section  38.  Any  person  who  violates,  diso- 
beys, omits,  neglects,  or  refuses  to  comply  with,  or  who 
resists,  any  of  the  provisions  of  this  ordinance,  or  who  re- 
fuses or  neglects  to  obey  any  of  the  rules,  orders  or  sanitary 
regulations  of  the  department  of  public  health,  or  who  omits, 
neglects,  or  refuses  to  comply  with,  or  who  resists  any  officer 
of  the  department  of  public  health,  or  order  or  special  regu- 
lation of  the  health  commissioner,  or  of  said  department  of 
public  health,  shall  upon  conviction  thereof,  before  any 
court  having  competent  jurisdiction,  be  subject  to  a  fine 
not  exceeding  One  Hundred  Dollars  ($100.00)  and  costs  of 
prosecution  or  imprisonment  in  the  city  prison  or  county  jail 
of County  for  a  term  not  exceeding  ninety  (90)  days." 


HEALTH  OFFICERS  425 

Duty  of  all  citizens.  One  point  cannot  be  too  strongly 
emphasized,  namely,  that  all  the  people  of  a  town  must 
cooperate  with  the  health  officer  in  order  to  produce  the 
best  results.  The  citizens  must  not  feel  that  they  have 
done  their  entire  duty  when  they  have  appointed  a  health 
officer.  He  is  greatly  handicapped  unless  he  has  the  in- 
telligent and  hearty  cooperation  of  the  people.  Every 
member  of  a  community 'should  cheerfully  obey  the  health 
ordinances  of  the  town.  Cases  of  contagious  diseases  and 
instances  of  violation  of  health  ordinances  should  be  re- 
ported to  the  proper  authorities.  Each  person  should  see 
that  the  conditions  around  his  home  are  healthful  and  that 
nothing  he  does  shall  be  a  menace  or  a  nuisance  to  his  neigh- 
bors. v 
COMMUNITY  PROJECT  5 

Purpose.     To  study  the  duties  of  the  local  health  officer. 

Directions,  i.  Information  should  be  obtained  regarding 
the  local  health  officers :  who  they  are,  how  they  were  appointed, 
and  what  they  are  doing.  A  copy  of  the  local  health  ordinances 
should  be  secured  and  discussed  in  class.  The  things  that  the 
members  of  the  class  can  do  to  cooperate  with  the  health  officers 
should  be  emphasized.  Find  how  much  money  per  capita  the 
town  is  spending  each  year  to  protect  the  health  of  the  com- 
munity. Compare  with  other  towns. 

2.  Make  a  study  of  the  parks  and  playgrounds.  What 
bearing  do  these  have  on  health  ? 

SUPPLEMENTARY  QUESTIONS  FOR  CLASS  DISCUSSION 

.   I .  What  should  the  people  do  to  help  the  health  officers  ? 

2.  How  do  the  health  officers  control  contagious  diseases  ? 

3.  What  can  they  do  to  keep  the  milk  and  food  supply  pure? 

4.  What  can  they  do  to  control  the  fly  and  mosquito? 

5.  What  are  the  health  officers  in  your  town  doing? 

6.  What  can  you  do  to  help  the  health  officer  in  his  work? 

REFERENCE 

Coleman,  The  People's  Health,  Macmillan  Co.,  New  York  City. 


CHAPTER  XXVII 
SCHOOL  HYGIENE 

1.  What  should  be  done  to  make  the  school 
building  a  healthful  place  in  which  to  stay  ? 

2.  What   sort   of   physical    defects    are   found 
among  school  children? 

In  recent  years  people  have  come  to  realize  that  it  is  most 
important  that  the  school  shall  look  after  the  health  of  the 
children,  because  success  both  in  school  and  outside  de- 
pends largely  on  health.  So  we  find  to-day  special  atten- 
tion is  being  given  to  the  health  of  school  children.  School 
doctors  and  nurses  are  employed  to  examine  children  and  to 
remedy  defects  of  eyes,  ears,  nose,  throat,  and  teeth.  In 
this  chapter  reference  will  be  made  to  two  lines  of  work 
being  carried  on  in  the  interest  of  the  children's  health : 
first,  the  provision  of  sanitary  schoolrooms  in  which  the 
child  works ;  and  second,  the  medical  inspection  of  children 
to  find  and  remedy  defects  and  sickness. 

Lighting  the  schoolroom.  In  the  construction  of  the 
schoolhouse,  lighting  is  one  of  the  important  things  to  con- 
sider. Plenty  of  light  in  a  room  is  necessary  for  the  best 
health  as  well  as  for  the  cheerfulness  of  the  room.  Improper 
methods  of  lighting  seriously  injure  the  eyes.  The  follow- 
ing points  need  to  be  considered :  first,  the  amount  of  light ; 
second,  the  direction  from  which  it  comes;  and  third,  the 
height  of  the  window  from  the  floor. 

In  general  the  amount  of  window  space  should  be  from 
one  sixth  to  one  fourth  of  the  floor  space.  During  the 
winter  there  is  less  light  than  in  the  fall  and  spring,  and  there 

426 


SCHOOL  HYGIENE  427 

should  be  enough  windows  to  provide  sufficient  light  during 
this  season,  as  well  as  on  cloudy  days. 

The  direction  from  which  the  light  comes  is  a  second  point 
to  consider.  It  should  not  come  from  the  front,  because 
it  would  then  shine  directly  into  the  children's  eyes,  and 
strain  them.  It  should  not  come  from  the  rear  because  the 
shadow  of  the  body  would  be  thrown  on  the  desk.  It  should 
not  come  from  the  right  because  the  shadow  of  the  hand  is 
thrown  on  the  reading  and  writing.  The  best  arrangement 
is  to  have  the  light  come  from  the  left. 

The  bottom  of  the  window  should  be  at  such  a  height  that 
it  is  above  the  level  of  the  eyes  of  the  children  when  they  are 
seated.  This  should  be  from  three  and  one-half  to  four  feet. 
If  it  is  lower  than  this,  it  strains  the  eyes  more  because  the 
light  shines  directly  into  them.  The  top  of  the  window 
should  reach  up  well  toward  the  ceiling,  as  the  light  from 
high  up  is  better  distributed  throughout \he  room. 

Heating  and  ventilating  the  building.  The  general  prin- 
ciples involved  in  heating  and  ventilating  the  school  build- 
ing are  the  same  as  those  involved  in  the  home,  which  were 
discussed  in  the  first  and  second  chapters.  But  in  the 
schoolroom  more  attention  should  be  given  to  ventilation 
than  is  ordinarily  done  in  the  home,  because  a  larger  number 
of  persons  are  gathered  in  one  room. 

Essentials  of  ventilation.  As  we  have  seen  in  Chapter  II, 
good  ventilation  requires  attention  to  the  following  matters ; 
a  constant  supply  of  fresh  air,  a  motion  of  air,  the  right  de- 
gree of  temperature,  and  the  right  per  cent  of  humidity. 

Fresh  air  and  motion.  To  keep  a  constant  supply  of  fresh 
air  requires  two  openings  in  a  room,  an  inlet  where  the  fresh 
air  enters  and  an  outlet  where  the  used  air  is  removed. 
Experiments  which  have  been  carried  on  show  that  the 
best  place  for  the  inlet  is  about  eight  or  nine  feet  from  the 
floor  and  that  the  best  place  for  the  outlet  is  within  a  foot 
of  the  floor  and  on  the  same  side  of  the  room  as  the  inlet. 


428 


SCIENCE  OF  HOME  AND   COMMUNITY 


Breathing  Zine 


Air  admitted  on  side. 
Discharged  near  bottom. 


t  Breathing  Line 


Outlet 


» 


In  securing  this  supply  of  fresh  air,  a  motion  of  air  is  pro- 
vided for  at  the  same  time. 

Gravity   system.     Various   methods   are  used  to  produce 
this  circulation  of  air.     One  system  is  called  the  gravity 

system.  In  this  system  the  mo- 
tion is  brought  about  through 
a  difference  in  the  weight  of 
the  air  due  to  a  difference  in 
temperature.  The  foul  air 
duct  is  connected  with  the 
chimney,  and  the  air  here  be- 
ing much  warmer  than  the  air 
outdoors  rises,  while  the  cold 
air  is  taken  in  at  the  basement 
and  after  being  heated  is  led 
into  the  various  rooms.  This 
may  work  fairly  well  in  cold 
climates  during  the  winter 
where  the  air  outdoors  is  much 
colder  than  that  in  the  school- 
room. But  in  the  fall  and 
spring,  when  the  difference  in 
temperature  is  small,  the  sys- 
tem is  not  satisfactory. 

Fans.  In  order  to  obtain 
the  best  circulation,  fans  are 
generally  used.  Two  systems 
are  used,  the  pressure  and  the 
exhaust.  In  the  pressure  system,  the  air  is  forced  into  the 
room  by  means  of  a  fan  located  in  the  basement.  In  the 
exhaust  system,  the  air  is  drawn  out  of  the  room  by  means 
of  a  fan  which  rotates  in  such  a  way  as  to  suck  the  air  out. 
If  only  one  of  these  systems  is  used,  it  should  be  the  pressure, 
as  that  is  generally  found  to  be  better.  Sometimes  both 
systems  are  used. 


jUr  admitted  at  bottom. 
Discharged  near  bottom. 


fn/ef  near  top. 
Dischorge  near  bottom. 

FIG.  169.  —  Inlets  and  outlets. 


SCHOOL  HYGIENE 


429 


Sometimes  two  methods  of  heating  are  employed.  Fresh 
air  is  forced  into  the  rooms  at  about  the  desired  temperature 
to  provide  ventilation,  and  the  exact  temperature  is  con- 
trolled by  means  of  steam  or  hot-water  radiators  placed  in 
each  room.  The  temperature  is  controlled  by  means  of 
thermostats  which  control  the  valves  on  these  radiators. 
This  combination  makes  a  very  satisfactory  heating  and 
ventilating  system,  when  properly  cared  for. 


FIG.  170.  —  School  ventilating  system  that  supplies  warm  air  of  correct  humidity. 

Ventilating  one-room  schools.  For  heating  small,  one- 
room,  rural  schools  a  jacketed  stove  is  widely  used.  The 
stove  is  surrounded  with  a  jacket  of  some  sheet  metal  which 
extends  down  to  the  floor  and  is  open  at  the  top.  Fresh 
air  is  brought  in  from  the  outside  by  means  of  a  duct  con- 
necting with  the  jacket.  As  the  air  is  heated,  it  rises  and 
passes  out  into  the  room.  The  foul  air  is  removed  by  means 
of  an  opening  in  the  chimney  near  the  floor  or  by  means  of 
a  pipe  connected  with  the  chimney  and  extending  down  to 
within  a  foot  of  the  floor. 


430  SCIENCE  OF  HOME  AND   COMMUNITY 

Amount  of  air  needed.  There  is  some  difference  of  opinion 
as  to  just  how  much  fresh  air  a  child  needs  each  minute. 
There  is  a  requirement  in  some  states  that  enough  air  should 
be  brought  into  the  room  so  as  to  provide  each  pupil  with 
thirty  cubic  feet  of  air  per  minute.  These  figures  were 
based  on  some  theories  which  have  been  partly  abandoned, 
and  some  authorities  to-day  say  that  pupils  do  not  need  this 
amount  of  fresh  air.  However,  until  we  have  more  definite 
knowledge  regarding  this  matter,  we  can  well  afford  to  be 
on  the  safe  side  of  furnishing  too  much  rather  than  too  little 
fresh  air.  The  nearer  we  can  approach  the  outside  con- 
ditions of  abundant  fresh  air  the  better  off  we  shall  be. 
The  air  must  be  changed  often  enough  to  remove  the  un- 
pleasant odor  arising  from  small  particles  given  off  from 
clothing  and  bodies. 

Temperature.  The  best  temperature  varies  in  accord- 
ance with  a  number  of  factors,  such  as  the  clothing  worn 
by  the  children  and  the  kind  of  school  work  being  done, 
whether  active  or  passive.  It  also  depends  on  the  humidity. 
In  the  dry  atmosphere  found  in  most  school  buildings  the 
proper  temperature  is  about  sixty-eight  degrees.  If  moisture 
is  added  to  bring  up  the  proper  per  cent  of  humidity,  a  tem- 
perature of  sixty-five  is  sufficient.  The  temperature  may 
be  kept  even  by  means  of  a  thermostat.  If  the  temperature 
runs  too  high,  the  thermostat  shuts  out  the  warm  air  and 
opens  the  cold  air  damper  wider,  and  if  the  temperature  is 
too  low,  the  thermostat  causes  a  reversal  of  this  action. 
Sometimes  the  thermostat  shuts  and  opens  the  valves  con- 
trolling the  steam  entering  the  radiators. 

Humidity  in  schoolrooms.  During  the  colder  portions  of 
the  year  the  humidity  of  our  schoolrooms  is  too  low.  One 
great  defect  in  our  ventilating  systems  is  that  they  do  not 
have  arrangements  to  increase  the  humidity.  The  average 
humidity  of  schoolrooms  in  winter  ranges  from  twenty  to 
thirty  per  cent.  This  is  a  very  dry  air  and  is  detrimental 


SCHOOL  HYGIENE 

to  the  health  of  those  living  in  it,  as  explained  in  Chapter  II. 
Experiments  which  were  carried  on  at  Yale  University  showed 
that  when  the  air  was  kept  at  the  proper  humidity,  the 
pupils  were  able  to  do  better  mental  work,  and  were  freer 
from  colds  than  when  the  humidity  was  low.  Experiments 
show  that  the  proper  per  cent  of  humidity  for  the  school- 
room is  about  fifty. 

How  humidity  is  determined.  One  may  naturally  ask  at 
this  point,  "  How  can  one  tell  what  the  per  cent  of  humidity 
in  a  room  is?  "  This  is  determined  by  an  instrument  called 
a  psychrometer.  This  consists  of  two  ordinary  thermom- 
eters, one  of  which  has  a  piece  of  wet  cloth  fastened  over  the 
bulb.  We  have  often  noticed  that  when  our  hands  are  wet 
on  a  cold  day  they  are  colder  than  when  dry.  This  is  be- 
cause the  water  evaporates  and  when  it  does  so,  it  makes 
things  colder  around  it;  that  is,  it  requires  heat  and  takes 
it  from  the  surrounding  bodies.  On  hot  days  sidewalks 
are  often  sprayed  with  water  to  cool  off  the  surrounding 
air. 

In  a  similar  way,  the  water  in  the  cloth  on  the  bulb  of  the 
thermometer  evaporates  and  lowers  the  temperature  of  the 
thermometer,  so  that  if  the  readings  of  the  two  thermom- 
eters are  taken,  the  one  with  the  wet  cloth  will  be  found  to 
be  lower.  The  difference  between  these  two  thermometers 
varies  from  day  to  day.  The  amount  of  water  that  evapo- 
rates, and  hence  the  lowering  of  the  temperature,  depends 
on  the  amount  of  moisture  in  the  air.  If  the  air  is  saturated, 
no  water  will  evaporate,  and  hence  there  will  be  no  difference 
in  the  readings  of  the  two  thermometers.  On  the  other 
hand,  if  the  air  is  very  dry  a  large  amount  of  water  will 
evaporate,  and  the  reading  of  the  wet  bulb  will  be  much 
lower  than  that  of  the  dry  bulb.  In  general,  then,  a  small 
difference  between  the  two  bulbs  means  a  high  per  cent  of 
humidity,  while  a  large  difference  means  a  low  per  cent  of 
humidity.  Tables  have  been  worked  out  by  which,  if  one 


43  2 


SCIENCE  OF  HOME  AND   COMMUNITY 


reads  the  two  thermometers,  it  is  possible  to  find  at  once 
the  per  cent  of  humidity.     (See  Appendix.) 

In  order  to  get  an  accurate  reading,  the  thermometers 
should  be  fanned  for  a  few  minutes,  or  even  better  they  may 
be  attached  to  a  board  which  can  be  rotated  in  the  hand  by 
means  of  a  handle.  This  is  called  a  sling  psychrometer. 

Humidifiers.     While  many  of  the  older  buildings  have 
made  no  arrangement  for  adding  water  to  the  air,  a  number 
of  satisfactory  systems  have  been  devised  and  are  being 
introduced  into  the  better  and  newer  build- 
ings.     In  one  system,   steam  is  allowed 
to  escape  through  small  holes  in  pipes 
placed  in  the  cold  air  duct.     Instead  of 
steam,  water  may  be  forced  in  as  a  spray 
through  nozzles. 

Another  plan  is  to  have  large  pans  of 
steaming  hot  water  in  the  cold  air  duct. 
In  still  another  plan,  a  rotating  cylinder  is 
placed  in  the  fresh  air  duct.  This  is  cov- 
ered with  a  coarse  meshed  cloth,  and  as 
the  cylinder  revolves  the  lower  edge 
passes  through  a  trough  filled  with  water. 
Thus  the  cloth  is  kept  moist  and  dripping 
all  the  time.  As  thermostats  are  used  to  regulate  the  tem- 
perature, so  humidostats  are  used  to  control  the  humidity. 


FIG.  171. —  Paper  tow- 
els, a  sanitary  substi- 
tute for  the  danger- 
ous public  towel. 


DEMONSTRATION  33 

Purpose.  To  see  if  the  ventilating  system  of  your  school 
furnishes  the  essentials  of  good  ventilation. 

Apparatus.     Touch  paper,  down,  two  thermometers. 

Directions,  i.  Amount  of  air  entering  the  room.  Throw  a 
tuft  of  down  in  front  of  the  air  inlet  and  estimate  how  far  it 
travels  in  a  second.  Try  several  times  and  take  the  average. 
Measure  the  dimensions  of  the  air  inlet.  Find  its  area.  Multi- 
ply this  by  the  velocity  of  air  just  found  so  as  to -compute  the 


SCHOOL  HYGIENE 


433 


number  of  cubic  feet  of  air  that  enter  the  room  each  second ; 
then  find  it  for  each  minute.  Multiply  the  number  of  pupils 
in  the  class  by  thirty,  which  has  been  set  as  the  standard  num- 
ber of  cubic  feet  that  should  be  furnished  each  pupil  per  minute. 
How  does  the  amount  of  air  entering  the  room  compare  with 
this  product  ? 

2.  Air  currents.     Light  a  piece  of  touch  paper  or  a  joss  stick 
and  hold  in  various  parts  of  the  room  to  determine  the  direction 
and  strength  of  the  air  currents.     Make  a  diagram  of  the  room 
on  the  board  and  indicate  the  direction  of  the  currents  by  means 
of  arrows. 

3.  Temperature.     Place    a    thermometer    in    different    parts 
of  the  room  and  find  the  temperature.     Try  on  several  days. 
Compare  with  the  standard  of  68°. 

4.  Humidity.     Test  the  humidity  as  explained  in  Demon- 
stration 8,  page  25.     Compare  with  the  standard  of  50°  to  60°. 
Find  the  humidity  outdoors. 

5.  Which  of  the  four  essentials  of  venti- 
lation   are    provided   in    the    schoolroom? 
Which  are  lacking  ?    How  may  the  deficiency 
be  remedied? 

Sanitary     drinking     fountains.       The 

common  drinking  cup  should  be  abolished 
from  every  school.  It  is  one  means  by 
which  such  diseases  as  tuberculosis,  diph- 
theria, mumps,  pneumonia,  and  other 
common  infectious  diseases  are  trans- 
mitted. Even  well  children  may  serve  as 
carriers  of  disease  germs  in  their  mouth, 
so  that  the  common  drinking  cup  is  a 
public  nuisance  and  a  source  of  danger 
wherever  found.  An  individual  drinking 
cup  may  be  made  out  of  a  piece*  of  clean 
paper  as  shown  in  figure  154.  With  the  many  types  of 
drinking  fountains  now  available,  there  is  no  excuse  for 
allowing  the  public  cup  to  be  used  any  longer.  Even  where 
2  F 


FIG.  172.  —  Fountain 
faucet. 


434  SCIENCE  OF  HOME  AND   COMMUNITY 

running  water  is  not  available,  there  can  be  obtained  water 
jars  to  which  sanitary  drinking  fountains  are  attached. 

Playground.  A  properly  equipped  school  needs  a  large 
playground.  One  great  defect  of  our  schools  in  the  country , 
as  well  as  in  the  city,  is  the  small  size  of  the  playground. 
Whenever  a  new  building  is  being  planned,  provisions  should 
be  made  for  adequate  playgrounds,  with  room  for  baseball 
grounds,  tennis  courts,  and  open  spaces  for  other  games. 
Play  is  an  essential  part  of  a  child's  life.  It  not  only  fur- 
nishes the  physical  exercise  that  the  growing  child  needs, 
but  it  also  has  a  distinct  educational  value  in  itself. 

Open-air  schools.  During  recent  years  open-air  schools 
have  been  established  for  tuberculous  and  sickly  children 
unable  to  attend  the  regular  school.  Sometimes  these  are 
entirely  in  the  open,  sometimes  they  are  provided  with  a 
roof,  and  sometimes  an  ordinary  room  is  changed  into  an 
open-air  school  by  hingeing  the  windows  at  the  top  and 
opening  them  to  their  fullest  capacity.  For  the  colder 
seasons  the  children  are  provided  with  special  clothing  to 
keep  them  warm.  These  schools  have  proved  almost  uni- 
versally successful  in  that  the  children  have  made  great 
gains  physically  and  are  able  to  do  better  work  in  their 
school  subjects.  If  these  open-air  schools  are  good  for  weak 
and  sickly  children,  we  are  naturally  led  to  inquire  why 
they  would  not  also  be  good  for  the  ordinary  child. 

Defects  in  school  children.  Having  seen  that  the  con- 
ditions under  which  children  study  are  healthful  and  sanitary, 
the  next  step  in  looking  after  children's  health  is  to  examine 
the  child  himself  and  see  if  he  is  handicapped  by  any  physical 
defects  that  can  be  remedied.  All  over  the  country,  chil- 
dren are  now  being  examined  and  the  results  show  that 
more  than  half  of  all  children  have  some  defects  of  the  ear, 
eye,  teeth,  throat,  or  nose.  In  many  cases  neither  the  chil- 
dren nor  their  parents  know  that  these  defects  exist.  When 
these  defects  have  been  discovered,  in  most  cases  they  can  be 


SCHOOL  HYGIENE 


435 


remedied,  and  thus  the  children  are  made  happier  and  better 
able  to  do  their  work.  The  results  of  the  examinations  of 
hundreds  of  thousands  of  children  in  all  parts  of  the  United 
States  are  shown  in  the  following  table  in  the  first  two  col- 
umns. The  last  column  is  obtained  by  estimate  through 
multiplying  the  number  of  school  children  in  the  United 
States  (about  twenty  million)  by  the  per  cents  obtained 
from  those  children  who  have  been  examined. 

TABLE  SHOWING  DEFECTS  OF  CHILDREN 


KIND  OF  DEFFCT 

PER  CENT 
AFFECTED 

TOTAL  NUMBER  IN  U.  S. 
AFFECTED 

Defects  of  ear 

2 

4.00  ooo 

Defects  of  nose  and  throat     .     .     . 
Defects  of  eye  . 

20 
2S 

4,000,000 

e  OOO  OOO 

Defects  of  teeth     

65 

13,000,000 

It  is  found  that  only  about  one  third  of  the  children  are 
free  from  defects,  about  one  third  have  defects  of  teeth  alone, 
and  the  remaining  third  have  defects  ?f  the  teeth  and  in 
addition  at  least  one  other  defect. 

Defective  teeth.  The  most  common  of  all  defects  are  those 
of  the  teeth.  From  two  thirds  to  three  fourths  of  all  chil- 
dren are  found  to  have  defective  teeth.  This  may  include 
every  stage  from  a  small  decaying  spot  to  teeth  which  are 
almost  entirely  decayed.  Of  all  teeth  examined  about  one 
fifth  are  defective. 

How  defective  teeth  affect  health.  Defective  teeth  may 
prove  injurious  to  health  in  three  ways :  first,  the  power  of 
mastication  of  food  is  decreased;  second,  the  pus  from  the 
decaying  teeth  when  absorbed  into  the  blood  or  taken  into 
the  stomach  has  an  injurious  effect;  and  third,  decaying 
teeth  may  be  the  breeding  place  of  bacteria  that  cause 
disease,  such  as  rheumatism  and  heart  disease.  Some  very 


436  SCIENCE  OF  HOME  AND   COMMUNITY 

remarkable  cures  of  rheumatism  have  been  effected  by  simply 
cleaning  the  teeth. 

Purposes  of  mastication.  Mastication  serves  many  useful 
purposes  as  we  have  already  learned  in  Chapter  V.  These 
uses  may  be  briefly  summarized  as  follows:  first,  mastica- 
tion grinds  the  food  into  a  fine  mass  and  thus  prepares  it 
for  the  process  of  'digestion  which  takes  place  in  the  stomach 
and  intestines ;  second,  the  thorough  mixture  with  the 
saliva  begins  the  act  of  digestion  of  the  starch;  third, 
thorough  mastication  better  enables  one  to  determine  how 
much  food  and  what  kinds  he  should  eat;  fourth,  it  pro- 
vides the  necessary  stimulus  for  the  normal  growth  of  the 
teeth  and  jaw;  fifth,  thorough  mastication  helps  to  clean 
the  teeth.  t  When  the  teeth  are  defective,  mastication  is 
done  less  thoroughly,  and  hence  these  purposes  are  ful- 
filled less  successfully. 

Dental  clinics.  Dental  clinics  are  now  being  introduced 
into  many  of  our  cities.  The  teeth  of  the  children  are  ex- 
amined and  treated  free  by  dentists  hired  by  the  school 
authorities.  As  teachers  are  hired  to  teach  children  how 
to  read,  so  dentists  are  hired  to  look  after  the  children's  teeth. 
These  clinics  are  very  common  in  Europe,  and  are  rapidly 
increasing  in  number  in  this  country.  Eventually  these 
clinics  will  doubtless  be  found  in  every  city  and  town. 
When  a  town  is  too  small  to  afford  it,  several  towns  may 
join  together  to  hire  a  dentist.  One  agricultural  paper  sug- 
gests that  a  new  "  R.  F.  D."  be  established,  —  "  rural  free 
dentistry." 

Defects  of  the  eye.  About  one  quarter  of  all  children  are 
suffering  from  defects  of  the  eye.  In  order  to  understand 
what  these  defects  are,  we  shall  need  to  examine  the  eye 
to  see  how  it  is  constructed  and  how  it  works.  We  may 
compare  it  with  a  camera.  The  eyeball  corresponds  to  the 
camera  box,  the  lens  in  the  eye  to  the  camera  lens,  the  iris 
and  the  pupil  of  the  eye  to  the  diaphragm  of  the  camera, 


SCHOOL  HYGIENE  437 

and  the  retina  which  lines  the  eye  corresponds  to  the  sensi- 
tive surface  on  the  film  or  glass  on  which  the  picture  is  taken. 

In  the  average  good  eye,  rays  of  light  pass  through  the 
eye  lens  and  are  focused  on  the  retina,  where  an  inverted 
image  is  formed  m  each  eye.  This  causes  impulses  to  pass 
along  nerves  to  the  brain,  which  give  us  the  sensation  of  a 
single  image  right-side  up.  The  brain  inverts  the  images 
and  causes  us  to  see  one  image  instead  of  two. 

Kinds  of  defects.  There  are  three  common  defects  of 
the  eye:  nearsightedness,  farsightedness,  and  astigmatism. 
In  nearsightedness,  the  rays 
of  light  come  to  a  focus  be- 
fore they  reach  the  retina, 
and  hence  the  image  is 
blurred.  In  farsightedness, 
the  rays  would  focus  behind 
the  retina  if  they  could  pass 
through  this.  In  astigma- 
tism, the  curvature  of  the 
lens  is  not  the  same  in  all 

riG.  173.  —  section  ot  the  human  eye. 

directions  and  while  a  ver- 
tical line  may  be  clearly  focused,  a  horizontal  line  is  blurred. 
The  eye  attempts  to  remedy  these  defects  by  accommoda- 
tion; but  this  involves  a  straining  of  the  eye  muscles,  es- 
pecially in  farsightedness  and  astigmatism,  and  if  carried 
too  far,  results  in  eye  ache  and  headache. 

Remedies.  The  remedy  for  nearsight  is  a  concave  lens. 
This  helps  to  throw  the  focus  further  back  on  the  retina. 
The  remedy  for  farsight  is  a  convex  lens.  This  brings  the 
light  to  a  focus  more  quickly.  The  remedy  for  astigmatism 
is  a  lens  with  unequal  curvature  in  different  directions  to 
offset  the  curvature  of  the  eye  lens. 

The  science  of  the  oculist  has  developed  so  far  that  most 
of  these  common  defects  can  be  easily  remedied  by  the  use 
of  spectacles.  In  the  case  of  a  very  nearsighted  person,  a 


438 


SCIENCE  OF  HOME  AND  COMMUNITY 


pair  of  spectacles  brings  about  a  most  remarkable  change 
in  enabling  him  to  see  things  he  has  never  seen  before,  so 
that  all  life  takes  on  a  new  aspect.  Glasses  should  be  fitted 
only  by  a  competent  oculist. 

School  work  requires  so  much  use  of  the  eyes  that  care 
should  be  taken  to  reduce  as  much  as  possible  the  strain  on 
the  eyes.  There  should  be  the  proper  amount  and  kind  of 
light  in  the  schoolroom.  The  books  used  should  be  printed 
on  good  paper  and  the  type  should  be  plain  and  large, 
especially  for  growing  children,  larger  than  that  required 
for  adults.  An  excessive  amount  of 
written  and  home  work  should  be 
avoided. 

Testing  the  eyes.  Nearsightedness 
may  be  easily  detected  by  means  of 
the  Snellen  card.  This  is  a  card 
with  a  series  of  letters  of  different 
sizes  showing  the  distance  at  which 
each  size  of  the  letter  can  be  seen  by 
the  average  eye.  Each  eye  is  tested 
separately,  and  if  a  person  is  near- 
sighted, it  is  shown  by  the  inability  to  read  the  letters  at 
the  standard  distance.  Farsightedness  may  be  tested  by  the 
same  card,  and  is  shown  if  a  child  can  see  a  line  of  letters  at 
a  greater  distance  than  that  marked  on  the  card.  To  test 
for  astigmatism,  a  card  is  used  containing  a  number  of  lines 
extending  in  different  directions  from  a  common  center  like 
spokes  of  a  wheel.  Astigmatism  is  shown  if  certain  lines 
appear  blacker  than  others. 


FIG.  174.  —  Lines  to  test 
astigmatism. 


DEMONSTRATION  34 

Purpose.     To  test  the  eyes  of  the  members  of  the  class. 

Apparatus.     Snellen's  vision  chart. 

The  eyes  of  the  members  of  the  class  may  be  tested  by  using 


SCHOOL  HYGIENE  439 

Snellen's  vision  chart.     Follow  the  directions  that  accompany 
the  chart. 

DEMONSTRATION  35 

Purpose.     To  illustrate  the  working  of  the  eye. 

Apparatus.  Reading  lens,  cardboard,  candle,  concave  lens, 
convex  lens. 

Directions,  i.  To  show  how  the  image  is  formed.  Hold  the 
reading  glass  and  the  cardboard  in  line  with  the  window  till 
images  appear  distinct  on  the  cardboard.  To  what  in  the  eye 
do  the  cardboard  and  lens  correspond?  How  does  the  image 
differ  from  the  object? 

2.  To  illustrate  the  conditions  for  nearsightedness.     Set  a  lighted 
candle  on  a  table  and  place  a  piece  of  white  cardboard  about 
two  feet  away.     Put  the  reading  glass  between  the  two  in  such 
a  way  that  an  image  of  the  candle  appears  on  the  cardboard. 
To  show  nearsightedness,  move    the   cardboard   farther  away 
from  the  lens  till  the  image  is  blurred.     To  show  the  remedy, 
put  a  concave  lens  in  front  of  the  reading  glass. 

3.  To  illustrate  the  conditions  for  farsightedness.     Set  up  the 
cardboard,  candle,  and  reading  glass  as  in  the  previous  experi- 
ment, till  the  image  is  clear.     Then  move  the  cardboard  nearer 
the  lens   till  the  image  is   blurred.     This   illustrates   farsight. 
To  show  the  remedy,  place  a  convex  lens  in  front  of  the  reading 
glass. 

Defects  of  nose  and  throat.  Defects  of  the  nose  and  throat 
are  quite  common.  About  two  million  children  in  the 
United  States  are  suffering  from  obstructed  breathing.  The 
two  most  common  defects  are  adenoids  and  enlarged  tonsils. 
These  tend  to  obstruct  the  nasal  passages  and  cause  mouth 
breathing.  This  is  not  as  healthful  as  nose  breathing  be- 
cause when  air  passes  through  the  nose  it  is  filtered  of  dust 
and  bacteria,  warmed,  and  humidified.  In  some  cases  these 
obstructions  interfere  seriously  with  the  mental  develop- 
ment of  the  child.  Inflammation  of  the  nose  and  throat 
often  spreads  to  the  ear  through  the  eustachian  tube  and 


440 


SCIENCE   OF  HOME   AND   COMMUNITY 


causes  deafness.  In  many  cases  the  difficulty  may  be  reme- 
died by  a  simple  operation  in  which  the  tonsils  or  adenoids 
are  removed. 

Defects  of  the  ear.  A  small  per  cent  of  children  have  de- 
fects of  the  ear.  The  chief  cause  of  these  defects  is  a  dis- 
eased condition  of  the  throat  and  nose.  Hence  it  is  important 
to  give  proper  care  to  these  troubles  before  they  spread  to 
the  ear.  Two  other  causes  of  defective  hearing  are  infectious 
diseases  and  stoppage  of  the  ear  canal.  The  diseases  which 


FIG.  175.  —  Before  and  after  removal  of  adenoids. 

are  most  apt  to  affect  the  ear  are  scarlet  fever,  measles,  and 
diphtheria.  Wax  accumulations  sometimes  cause  deafness. 
If  taken  in  time,  the  wax  may  be  easily  removed.  This 
should  be  done  only  by  a  doctor.  It  is  dangerous  to  run 
hair  pins  and  other  objects  into  the  ear  in  order  to  remove 
the  wax,  as  some  people  carelessly  do. 

The  ears  may  be  tested  by  means  of  a  watch.  The  person 
should  be  blindfolded  and  each  ear  tested  separately.  The 
watch  is  held  at  varying  distances  and  the  greatest  distance 
at  which  it  can  be  heard  is  ascertained.  Meanwhile  the 
other  ear  should  be  covered. 


SCHOOL  HYGIENE  441 

Medical  inspection  of  school  children.  The  state  re- 
quires the  child  to  attend  school  until  a  certain  age  is  reached. 
At  school  the  child  is  exposed  to  some  dangers  that  he  would 
not  encounter  at  home.  Since  the  law  compels  a  child  to 
attend  school,  the  law  must  protect  his  health  while  there. 
Compulsory  medical  inspection  of  schools  must  naturally 
follow  compulsory  attendance.  In  some  states  medical 
inspection  is  compulsory,  and  eventually  this  will  doubtless 
be  required  in  all  states. 

Medical  inspection  has  two  large  purposes  :  first,  to  detect 
infectious  diseases ;  and  second,  to  detect  and  remedy  any 
defects  of  eye,  ear,  etc.,  that  interfere  with  the  child's  develop- 
ment. The  school  is  the  best  place  to  detect  and  control 
infectious  diseases,  so  that  the  other  children  and  the  entire 
community  may  be  protected. 

In  the  larger  cities  a  corps  of  competent  doctors  and  nurses 
should  be  hired  to  carry  on  this  work.  The  chief  work  of  the 
doctors  is  to  discover  the  defects ;  the  nurse  follows  up  the 
cases  and  visits  the  home  and  tries  to  see  that  the  parents  give 
the  child  the  needed  treatment.  In  some  cities  clinics  are 
being  established  where  children  are  treated  for  their  defects 
if  the  parents  are  too  poor  or  too  careless  to  have  it  done. 
It  seems  natural  and  logical  not  only  to  find  out  the  defects, 
but  also  to  remedy  them. 

In  some  smaller  towns  which  cannot  afford  to  hire  both 
a  doctor  and  a  nurse,  it  is  found  that  a  nurse  alone  can  do 
very  effective  work,  and  many  of  our  towns  and  small  cities 
are  employing  a  school  nurse,  who  is  the  most  important 
single  factor  in  the  work  of  medical  inspection  because  she 
is  constantly  on  duty  and  visits  the  homes. 

Advantages  of  medical  inspection.  Medical  inspection  is 
found  to  have  the  following  advantages :  first,  it  is  a  means 
of  preventing  the  spread  of  infectious  diseases ;  second, 
school  work  proceeds  more  successfully  because  there  is  a 
saving  of  time  that  might  otherwise  be  lost  on  account  of 


442  SCIENCE   OF  HOME   AND   COMMUNITY 

sickness  and  the  children  are  able  to  do  better  school  work 
because  they  are  in  better  health ;  .third,  it  makes  the  child 
happier  and  gives  him  a  better  chance  in  life ;  fourth,  it  is  a 
means  of  educating  the  public  on  the  matter  of  health. 

Work  of  nurse  and  doctor.  In  working  out  a  system  of 
medical  inspection  the  following  things  are  done  by  the 
doctor  or  nurse.  First,  a  thorough  examination  is  made 
of  every  child  when  he  enters  school ;  second,  a  daily  ex- 
amination is  made  of  all  children  reported  as  ill  by  the 
teacher;  third,  after  a  child  has  been  out  of  school,  he 
is  examined  when  he  returns ;  fourth,  occasional  examina- 
tions are  made  by  the  nurse  of  the  eyes,  ears,  teeth,  nose, 
and  throat ;  fifth,  frequent  inspections  are  made  to  detect 
contagious  diseases  and  these  cases  are  referred  to  the 
board  of  health ;  sixth,  the  school  nurse  looks  after  the 
minor  ailments  and  gives  instructions  in  practical  lessons 
in  hygiene  to  the  children ;  seventh,  the  school  nurse  follows 
up  the  cases  when  defects  are  reported,  by  visiting  the  homes 
and  encouraging  the  parents  to  have  the  children  treated ; 
eighth,  in  cases  where  the  parents  cannot  or  do  not  see  that 
the  child  receives  the  necessary  treatment,  the  school  should 
have  it  done.  This  may  be  done  through  private  means 
or  at  public  expense. 

SCHOOL  PROJECT  8 

Purpose.     To  make  a  sanitary  survey  of  the  school. 

Direction.  Procure  a  copy  of  Hoag  and  Termann's  Health 
Work  in  the  Schools,  published  by  Houghton  Mifflin  Co.,  Boston. 
Make  a  survey  of  your  school  following  the  outline  given  on 
pages  246-248.  As  a  result  of  this  survey  would  you  say  that 
the  sanitary  conditions  in  your  school  are  satisfactory?  If  not, 
what  is  lacking?  What  can  be  done  to  remedy  these  defects? 


SCHOOL  HYGIENE  443 

SUPPLEMENTARY  QUESTIONS  FOR  CLASS  DISCUSSION 

1 .  What  are  the  proper  methods  of  lighting  the  schoolroom  ? 

2.  What  are  the  best  ways  of  heating  and  ventilating  the 
schoolroom  ? 

3.  Does  the  system  used  in  your  schoolroom  furnish  the 
essentials  of  ventilation  ? 

4.  In  what  ways  may  a  circulation  of  air  be  maintained  in 
the  schoolroom? 

5.  How  may  the  per  cent  of  the  humidity  of  a  room  be 
determined  ? 

6.  How  may  the  proper  amount  of  moisture  be  introduced 
into  the  room  ? 

7.  Why  should  the  public  drinking  cup  be  abolished? 

8.  What  is  the  purpose  of  medical  inspection  of  schools? 

9.  Why  is  medical  inspection  of  Schools  extremely  desirable 
and  almost  necessary? 

10.  Why  is  the  school  nurse  a  very  important  factor  in  a 
system  of  medical  inspection  ? 

1 1 .  What  effect  have  defective  teeth  on  health  ? 

12.  How  may  the  defects  of  the  eye  be  remedied? 

13.  What  harm  is  done  to  health  by  adenoids  and  enlarged 
tonsils  ? 

REFERENCE 

Dresslar,  School  Hygiene,  Macmillan  Co.,  New  York  City. 


SECTION   D 

COMMUNITY  ENTERTAINMENT 

CHAPTER  XXVIII 
MOVING   PICTURES 

How  are  moving  pictures  made  and  how  are 
they  thrown  on  the  screen  ? 

No  application  of  science  during  the  last  ten  years  has 
had  such  a  rapid  development  and  become  used  by  so  many 
people  as  the  moving  pictures.  They  are  now  found  in 
all  parts  of  the  country,  and  almost  every  town  has  one  or 
more  moving-picture  theaters.  It  has  become  in  a  very 
real  way  the  people's  theater.  It  is  estimated  that  there  are 
fifteen  thousand  moving-picture  theaters  in  the  United 
States,  besides  many  halls  where  moving  pictures  have  been 
established,  and  that  these  have  an  average  daily  attendance 
of  fourteen  million  people  who  spend  each  day  for  admission 
fees  over  one  million  dollars.  There  are  shown  daily  in 
all  the  moving  pictures  a  total  of  about  eighteen  thousand 
miles  of  films,  almost  enough  to  encircle  the  earth. 
I,  Early  attempts.  Let  us  first  notice  some  of  the  early 
attempts  to  make  moving  pictures,  and  the  progress  that 
has  been  made  in  recent  years.  In  1872  Edward  Muybridge, 
a  resident  of  San  Francisco,  conceived  a  plan  of  taking  a 
series  of  pictures  in  rapid  succession.  His  plan  required 
the  use  of  a  large  number  of  cameras  that  were  set  up  side  by 
side.  About  ten  years  later,  Dr.  Marey  in  France  made 

444 


MOVING   PICTURES 


445 


improvements  on  the  plan  of  Mr.  Muybridge.  He  devised 
a  plan  by  which  all  the  pictures  were  taken  by  one  camera 
by  means  of  turning  .a  handle.  This  was  a  great  step  for- 
ward, because  it  reduced  the  expense  and  took  all  the  pictures 
from  one  viewpoint.  This  may  be  called  the  real  fore- 
runner of  the  modern  moving  picture  camera.  In  1886 
he  made  a  special  exhibi- 
tion of  the  results  that  he 
had  obtained. 

Developments  in  pho- 
tography. Before  any 
marked  progress  could  be 
made  in  the  development 
of  moving  pictures,  two 
improvements  in  photog- 
raphy were  necessary. 
These  were,  first,  the  sub- 
stitution of  films  for  glass 
plates,  and  second,  the 
making  of  a  more  sensitive 
surface  for  coating  the 
plate  so  that  the  pictures 
could  be  taken  with  a 
very  short  exposure. 

Celluloid  film.  The  development  of  a  sensitive  film  to 
take  the  place  of  glass  plates  was  made  by  Mr.  Eastman  of 
New  York  State.  Experiments  were  made  with  many  sub- 
stances in  the  attempt  to  find  one  that  was  transparent,  that 
could  be  made  in  thin  sheets,  and  that  was  sufficiently 
pliable  and  strong  to  be  wound  around  a  roller.  After  many 
failures,  Mr.  Eastman  made  a  celluloid  film  that  met  these 
requirements.  These  sheets  of  celluloid  are  coated  with 
sensitive  chemicals  for  making  the  negative.  In  1889  the 
first  long  strips  of  film  suitable  for  moving-picture  work 
appeared. 


FIG.  176.  —  Muybridge,  sometimes  called 
the  father  of  moving  pictures. 


446 


SCIENCE  OF  HOME  AND   COMMUNITY 


Edison's  kinetoscope.  While  Mr.  Eastman  had  been 
working  to  perfect  a  film,  Thomas  Edison  had  been  working 
.on  a  mechanism  to  show  the  pictures  to  the  public.  When 
the  film  was  perfected  by  Mr.  Eastman,  it  was  used  by  Mr. 
Edison  in  the  kinetoscope,  the  first  moving-picture  machine. 
^This  was  on  exhibition  at  the  World's  Fair  at  Chicago  in 
1893,  and  attracted  a  great  deal  of  attention.  It  was  a  box- 
like  structure,  containing 
a  slot.  When  a  nickel  was 
dropped  in  the  slot  and 
the  eye  applied  to  the 
opening,  pictures  passed 
before  the  eye  with  such 
rapidity  that  they  seemed 
to  be  alive.  Within  the 
box  was  a  long  film  of 
pictures  revolving  around 
a  series  of  spools.  Just 
below  the  peep  hole  was 
a  revolving  shutter.  A 
motor  caused  the  film  to 
move  across  the  field  of 
vision  and  the  shutter  to 
revolve  in  such  a  way  that 
a  series  of  pictures  was 
This  was  the  first  real  mov- 


FlG.  177.  —  Edison,  inventor  of  the  kineto- 
scope and  phonograph. 


•  presented  rapidly  to  the  eye. 

-  ing  picture. 

.  Although  this  attracted  much  attention,  it  was  looked 
upon  at  first  only  as  a  toy,  and  its  commercial  possibilities 
were  not  realized.  It  reminds  one  very  strongly  of  the 
reception  given  the  telephone  at  the  Centennial  Exhibition 
•at  Philadelphia  in  1876. 

Animatograph.  The  first  attempts  to  project  moving 
pictures  on  a  screen  so  that  they  might  be  seen  by  many 
people  at  the  same  time  were  made  in  England  by  Robert 


MOVING  PICTURES  447. 

W.  Paul.  He  called  his  machine  the  animate-graph.  ,  He 
invented  a  device  by  which  the  film  was  brought  into  a 
fixed  position  for  a  very  brief  space  of  time,  and  thus  enough, 
light  was  allowed  to  pass  through  to  make  the  images  distinct. 
This  was  first  successfully  operated  in  London  in  1895.  In 
the  following  year  a  public  demonstration  was  given,  and 
it  proved  highly  successful.  This  animatograph  was  intro- 
duced at  the  Olympia,  where  it  proved  ,the  most  attractive 
feature.  The  Olympia,  then,  was  the  first  moving-picture 
theater ;  and  in  Great  Britain  Robert  Paul  is  called  the 
father  of  the  moving  pictures. 

Cinematograph.  At  the  same  time  that  Robert  Paul  was 
experimenting  with  his  machine  in  England,  Messrs. .  Lumie~re 
and  Sons  were  working  on  the  same  problem  in  France. 
They  perfected  a  camera  for  taking  the  pictures  and  a  pro- 
jector for  throwing  them  on  the  screen.  They  called  their, 
machine  the  cinematograph.  These  proved  successful, 
and  were  used  in  France  about  the  time  the  Paul  machines 
were  first  used  in  England.  It  was  the  French  cinemato- 
graph which  was  introduced  into  America  and  laid  the 
foundation  for  the  development  of  moving  pictures  in  this 
country.  Although  it  was  the  invention  of  an  American, 
Thomas  Edison,  which  made  the  moving,  pictures  possible, 
they  were,  developed  in  both  England  and  France  before 
they  were  in  this  country.  The  first  moving  pictures  to 
appear  in  America  were  exhibited  in  1896  at  the  Eden  Musee. 

Having  noticed  briefly  the  history  of  the  moving  pictures, 
we  may  consider  more  carefully  how  the  pictures  are  pro- 
duced and  how  they  are  thrown  upon  the  screen. 

Making  the  film.  The  Eastman  Kodak  Company  alone 
manufactures  about  one  hundred  miles  of  film  daily.  In 
the  manufacture  of  the  film,  such  vegetable  materials  as 
flax  and  cotton  waste  are  used.  These  are  treated  with 
acids,  which  change  the  materials  to  gun  cotton.  This  is 
then  dissolved  in  wood  alcohol,  which  is  spread  out  in  a 


448  SCIENCE  OF  HOME  AND   COMMUNITY 

thin  mixture  over  smooth  surfaces,  where  it  is  allowed  to 
dry.  It  is  then  coated  with  the  sensitive  emulsion.  The 
sheet  is  then  cut  up  into  strips  one  and  three  eighths  inches 
wide,  which  is  the  standard  width  for  movie  cameras  and 
projectors.  The  materials  of  which  the  films  were  formerly 
made  were  highly  inflammable  and  their  use  was  attended 
with  danger  of  fire.  A  kind  of  material  has  now  been  made, 
however,  which  is  practically  non-inflammable. 

In  order  to  have  the  film  move  steadily  in  the  camera  and 
projector,  perforations  are  made  along  either  side  of  the  film 
by  means  of  machines.  The  standard  is  sixty-four  holes 
per  foot.  The  success  of  the  picture  depends  to  a  great 
extent  upon  the  accuracy  with  which  these  perforations  are 
made. 

Moving-picture  camera.  The  moving-picture  camera 
consists  of  three  parts,  the  camera  proper,  a  box  for  the  un- 
exposed  film,  and  a  box  for  the  exposed  film.  By  means  of 
a  handle  turned  by  hand,  the  film  is  unwound  and  brought 
before  the  shutter;  there  it  is  exposed,  and  then  wound  up 
in  the  other  box.  These  boxes  can  easily  be  detached  from 
the  camera;  and  when  one  film  is  used,  the  box  can  be  re- 
moved and  another  put  in  its  place.  The  motion  is  given 
to  the  film  by  turning  a  handle  attached  to  the  side  of  the 
camera.  This  is  so  constructed  that  the  film  moves  by 
jerks,  so  that  the  exposed  section  of  the  film  is  still  for  a 
fraction  of  a  second  while  the  picture  is  being  taken.  It 
requires  practice  to  be  able  to  turn  the  handle  at  the  right 
speed.  This  should  be  done  so  as  to  make  about  sixteen 
exposures  a  second.  Sometimes  the  handle  is  turned  by  a 
motor. 

When  the  end  of  a  series  of  exposures  is  reached,  the 
operator  pushes  a  film  punch  projecting  from  the  camera, 
which  makes  punch  marks  on  the  film.  The  number  of 
feet  of  film  that  has  been  used  is  indicated  automatically 
on  a  dial,  so  that  the  operator  may  know  when  to  change 


MOVING  PICTURES 


449 


the  film.     The  length  of  these  films  may  vary  from  three 
hundred  to  five  hundred  feet. 

When  an  object  is  to  be  taken  which  is  moving  both  hori- 
zontally and  vertically,  like  a  flying  machine,  a  special  kind 
of  tripod  is  used.  This  has  two  sets  of  gears  and  wheels, 
one  of  which  moves  the  camera  in  a  horizontal  plane,  while 
the  other  moves  it  up  and  down. 
This  requires  two  men  to  operate 
it,  one  to  turn  the  handle  for  tak- 
ing the  pictures,  and  the  other  to 
move  the  camera  so /that  the  ob- 
ject to  be  photographed  is  kept  in 
the  center  of  the  field  of  vision. 

Preparing  the  film  Special 
means  have  to  be  employed  for 
handling  long  films  in  develop- 
ment. The  films  are  wound 
around  long  wooden  frames  or 
reels.  The  principle  involved  is 
the  same  as  that  described  in 
Chapter  VII.  The  films  for  one 
subject  are  often  developed  in 
several  parts  and  then  are 
fastened  together  by  means  of 
a  transparent  cement.  There  is 
often  great  waste  in  the  film, 
sometimes  as  much  as  twenty  per 
cent  being  thrown  away  on  ac- 
count of  imperfections. 

In  order  to  make  a  positive  that  can  be  used  in  the  pro- 
jecting apparatus  another  strip  of  perforated  film  similar  to 
the  first  one  is  used,  except  that  it  is  less  sensitive  to  Kght. 
The  principle  is  the  same  as  that  involved  in  making  ordi- 
nary prints,  only  different  devices  must  be  used  on  account 
of  the  great  length  of  film. 

2G 


FIG.    178.  —  A    motion-picture 
printing  machine. 

A- A'  —  Rollers  for  negative  film ; 
B-B'  —  Rollers  for  positive  film; 
C  —  Film  gate  where  positive  is 

held  over  negative  for  printing ; 
E  —  Unexposed  positive  film ; 
E'  —  Exposed  or  printed  positive 

film; 
F —  light  which,  shining  through 

film   gate,  imprints    image    of 

negative  on  positive. 


450 


SCIENCE  OF  HOME  AND   COMMUNITY 


•  Throwing  pictures  on  the  screen.  For  showing  pictures 
on  the  screen,  three  essentials  are  needed:  a  projecting 
apparatus,  a  source  of  strong  light,  and  a  screen  or  white 
surface.  This  projecting  apparatus  is  the  same  in  principle 
as  the  stereopticon,  or  magic  lantern,  the  chief  difference 
being  in -the  mechanism  by  which  the  film  is  passed  through 
the  machine. 

Parts  of  a  stereopticon.     The  essential  parts  of  a  stereop- 
ticon are  shown  in  Figure  179.    These  consist  of  a  source  of 

light  A ;  a  set  of 
condensing  lenses  C, 
which  concentrate 
the  light  upon  the 
lantern  slide  5.  This 
is  focused  by  the  lens 
L  upon  the  screen  S'. 
This  lens  inverts 
the  image  so  that 
the  slide  is  placed 
in  the  holder  upside 
down. 


FIG.  179.  —  Stereopticon. 


Projecting  apparatus.  The  delicate  part  of  the  moving- 
picture  lantern  is  the  mechanism  by  which  the  film  is  passed 
through  the  machine.  This  film  must  have  an  intermittent 
motion,  the  same  as  in  the  camera,  so  as  to  stop  for  a  fraction 
of  a  second  to  allow  light  to  pass  through  and  throw  a  distinct 
image  on  the  screen.  The  film  is  mounted  on  a  spool  and 
led  over  a  toothed  sprocket,  which  fits  into  the  perforations. 
A  loop  is  then  formed,  and  the  film  passes  into  the  gate 
behind  the  lens.  As  the  shutter  revolves,  shutting  off  the 
light  from  the  picture,  the  film  is  given  a  jerk  downwards, 
thus  bringing  the  next  picture  into  the  gate,  in  exactly  the 
same  position  as  the  previous  one.  The  film  is  then  con- 
nected with  another  sprocket  and  finally  rolled  up  on  another 
spool.  The  machine  may  be  operated  either  by  hand  or  by 


MOVING  PICTURES  451 

motor.  These  pictures  are  thrown  upon  the  screen  at  the 
same  rate  at  which  they  are  taken,  about  sixteen  per  second. 
After  the  film  has  been  used,  it  must  be  rewound  on  another 
reel,  so  as  to  bring  the  first  picture  into  its  proper  position 
again. 

FIELD  EXERCISE  8 

Purpose.  To  visit  a  moving  picture  theater  to  see  how  the 
projecting  apparatus  works. 

Directions.  Arrangements  should  be  made  with  the  manager  of 
some  moving  picture  theater  to  have  the  class  visit  the  theater 
when  it  is  not  being  used,  in  order  to  see  how  the  projecting  ma- 
chine works.  The  operator  can  explain  the  details  of  the  opera- 
tion. At  the  next  meeting  of  the  class  the  points  observed  should 
be  discussed. 

Physiology  of  moving  pictures.  In  order  to  understand 
the  action  of  the  moving  pictures,  we  must  not  only  under- 
stand the  camera  by  which  they  are  taken,  and  the  pro- 
jector by  which  they  are  thrown  on  the  screen,  but  also  the 
eye  which  sees  them.  The  machine  throws  on  the  screen 
about  sixteen  pictures  a  second,  which  occupy  a  foot  of  film. 
The  screen  is  darkened  about  half  the  time.  Why  do  we 
not  see  these  as  so  many  distinct  pictures,  instead  of  as  a 
continuous  series  of  moving  pictures?  This  is  due  to  a 
peculiarity  in  the  action  of  the  eye.  Rays  of  light  pass 
through  the  pupil  and  are  focused  by  the  lens  on  the  retina 
of  the  eye.  This  is  lined  with  a  network  of  sensitive  nerves, 
so  that  when  the  image  is  formed  here,  impulses  pass  to  the 
brain,  and  we  have  the  sensation  of  sight.  Even  after  the 
object  is  removed  from  view,  the  image  still  lingers  in  the 
brain  for  about  one  twenty-fourth  of  a  second,  just  as  though 
the  object  were  in  full  view.  In  the  movies  the  pictures  are 
shown  so  rapidly  that  the  second  picture  is  shown  before  the 
image  of  the  first  leaves  the  brain.  Thus  the  brain  sees  a 
continuous  series  of  pictures  without  any  breaks  between, 


452  SCIENCE  OF  HOME  AND   COMMUNITY 

and  this  gives  the  appearance  of  motion.  Moving  pictures 
are  really  an  illusion  made  possible  through  this  peculiarity 
of  the  eye. 

A  picture  is  thrown  on  the  screen  and  remains  visible  for 
about  one  thirty-second  of  a  second;  then  the  screen  is 
darkened  for  about  the  same  length  of  time  by  the  passage 
of  the  shutter,  which  cuts  off  the  light.  Thus  the  pictures 
follow  one  another,  one  thirty-second  of  a  second  on  the 
screen  and  then  one  thirty-second  of  a  second  darkened. 
As  the  image  of  the  picture  stays  in  the  brain  one  twenty- 
fourth  of  a  second  after  the  picture  has  left  the  screen,  the 
brain  retains  this  impression  during  the  one  thirty-second 
part  of  a  second  that  the  shutter  cuts  off  the  light.  The 
image  of  the  second  picture  is  thus  impressed  on  the  brain 
before  the  first  leaves  it,  so  that  the  brain  does  not  see  the 
darkened  screen  at  all.  If  the  pictures  were  run  through 
slowly,  say  at  the  rate  of  only  five  or  six  a  second,  then  we 
could  distinguish  between  the  pictures  and  the  darkened 
screen. 

LABORATORY  EXERCISE  35 

Purpose.  To  illustrate  why  we  seem  to  see  a  continuous  set 
of  pictures  at  the  movies. 

(The  following  exercise  is  taken  from  Rowell's  Introduction  to 
General  Science.} 

Directions.  Obtain  a  piece  of  cardboard  about  three  inches 
square.  Punch  a  hole  in  each  of  two  opposite  ends.  Pass 
through  each  a  piece  of  string  about  fifteen  inches  long  and  tie 
the  ends  together,  making  a  loop.  On  one  side  draw  a  man's  head 
in  colors  or  paste  on  it  the  picture  of  a  man.  On  the  other  side 
draw  straight  vertical  lines.  Put  a  loop  over  each  thumb  and 
turn  the  cardboard  till  it  winds  up  the  strings.  To  put  the 
"  man  in  prison  "  pull  the  thumbs  apart  thus  giving  a  rapid 
rotary  motion  to  the  cardboard.  The  man  will  seem  to  be 
behind  prison  bars.  Explain  the  result.  How  does  this  prin- 
ciple hold  in  the  movies  ? 


MOVING  PICTURES 


453 


Science  and  moving  pictures.  Moving  pictures  have  been 
used  to  illustrate  many  interesting  things  in  nature.  In 
order  to  show  the  opening  of  a  flower  or  the  entire  growth  of 
a  plant  from  seed  to  blossom,  the  camera  is  focused  on  the 
object,  and  a  picture  is  taken  every  half  hour  or  so  during 
the  entire  period.  These  pictures  are  then  shown  rapidly 
on  the  screen,  and  what  really  takes  several  weeks  or  months 
in  nature  is  shown  here  in  a  few  minutes.  In  a  similar  way, 
iilms  show  the  development  of  caterpillars  into  butterflies, 
the  development  of  the  house  fly,  the  development  of  the 
chick  in  ~the  egg,  and  the 
breaking  of  the  egg.  A 
number  of  moving  pic- 
tures of  birds  feeding 
their  young  have  been 
made. 

Through  the  use  of  the 
microscope  moving  pic- 
tures have  been  taken  of 
such  small  objects  as  bac- 
teria. In  Connection  with  FIG.  180.  —  Birth  of  a  flower.  FUm  for 

the  use  of  X-rays,  pictures       ^dth  t^S  ^  0"  *  4th>  '* 

have  been  taken  showing 

the  motions  of  the  stomach  of  a  frog  during  the  process  of 

•digestion. 

"  Animated  newspaper . "  One  of  the  more  recent  develop- 
ments in  moving  pictures  is  the  animated  newspaper.  This 
is  edited  and  planned  in  a  way  similar  to  the  ordinary  paper. 
The  purpose  is  to  obtain  moving  pictures  of  the  more  im- 
portant daily  news  items  in  various  parts  of  the  country. 
Operators  are  kept  in  various  sections  of  the  country  to 
obtain  pictures  of  news  of  special  interest  in  these  different 
localities.  The  films  are  sent  to  the  main  offices  of  the 
paper,  where  positive  films  are  quickly  made  ready  to  send 
out  to  the  subscribers.  This  work  is  done  with  great  rapid- 


454  SCIENCE  OF  HOME  AND   COMMUNITY 

ity,  so  that  if  the  original  film  is  received  by  ten  o'clock  P.M., 
the  positive  films  are  ready  to  send  out  by  two  o'clock  the 
next  morning.  These  films  can  then  be  taken  out  by  the 
early  morning  trains.  These  papers  have  regular  subscribers 
among  the  showmen,  to  whom  the  films  are  sent  regularly. 
Some  of  these  papers  are  published  weekly,  some  twice  a 
week,  and  doubtless  in  the  near  future  they  will  be  published 
daily. 

Moving  pictures  in  the  schoolroom.  There  is  a  great  op- 
portunity for  the  use  of  moving  pictures  in  schoolrooms. 
Already  some  ..schools  are  being  equipped  with  moving- 
picture  outfits.  Geography  can  be  made  much  more  real 
by  means  of  moving  pictures.  Great  mountains,  lakes,  and 
rivers  are  easily  shown,  as  are  the  activities  of  people  in 
various  countries  showing  their  costumes  and  habits.  In 
fact  there  seems  almost  no  end  to  the  possibilities  of  moving 
pictures  in  geography.  In  elementary  science  many  things 
can  be  realistically  shown,  such  as  the  opening  of  a  flower, 
the  action  of  filings  around  a  magnet,  and  the  development 
of  the  house  fly.  There  are  also  great  possibilities  in  con- 
nection with  literature. 

Trick  pictures.  Many  unusual  effects,  impossible  in  real 
life,  are  produced  by  tricks  in  the  process  of  making  and 
showing  the  pictures.  In;  order  to  make  people  appear 
very  large  or  very  small,  pictures  are  taken  at  different 
distances,  thus  giving  different-sized  images.  Then  these 
two  films  are  printed  one  over  the  other  so  that  the  two 
images  appear  on  the  screen  at  the  same  time. 

In  picturing  accidents  the  camera  is  stopped  just  before 
the  accident  occurs  and  a  dummy  is  substituted  for  the  real 
actor,  and  then  the  camera  goes  on  taking  pictures.  Later 
the  dummy  may  be  removed  and  the  actor  come  back  again. 

In  order  to  show  reversed  action  such  as  a  pumpkin  rolling 
up  hill  or  smoke  going  down  a  chimney,  the  film  is  unrolled 
backwards,  the  last  picture  being  shown  first. 


MOVING  PICTURES 


455 


To  produce  action  of  inanimate  objects,  such  as  a  shoe 
lacing  itself,  a  series  of  pictures  is  taken  of  the  object  in 
different  positions  and  then  these  are  thrown  on  the  screen 
rapidly. 

The  apparent  walking  of  a  person  up  the  side  of  the  house 
is  produced  by  taking  pictures  with  a  camera  which  is  placed 
above  the  stage. 

Animated  cartoons.  One  of  the  more  recent  develop- 
ments of  the  movies  that  has  now  become  well  established 


Courtesy  of  Everybody's  Magazine. 

FIG.  181.  —  Drawings  for  animated  cartoons.     These  are  the  drawings  required  to 
show  the  whole  process  of  withdrawing  Mutt's  hand  and  closing  his  eye. 

is  the  animated  cartoon.  There  is  almost  no  limit  to  the 
ideas  that  may  be  worked  out  in  this  way.  These  cartoons 
are  made  by  taking  photographs  of  a  series  of  drawings. 
One  drawing  is  placed  before  a  camera  and  a  picture  taken, 
than  another  drawing  and  another  picture  taken,  and  so  on 


456  SCIENCE  OF  HOME  AND   COMMUNITY 

till  pictures  have  been  taken  of  all  the  drawings.  The 
pictures  made  from  these  exposures  are  shown  rapidly  on 
the  screen,  so  that  a  series  of  drawings  that  are  seen  by  the 
audience  in  eight  minutes  took  an  artist  five  weeks  to  make. 
In  order  to  procure  a  half  reel  (about  500  feet)  of  animated 
cartoons  about  2000  drawings  must  be  made.  Some  idea 
of  the  number  of  drawings  required  may  be  gained  by  ex- 
plaining that  in  the  Mutt  and  Jeff  pictures  it  takes  four 
drawings  to  show  Mutt  withdrawing  his  hand  from  his 
pocket  and  three  drawings  to  show  him  winking  his  eye. 
In  order  to  make  the  Mutt  and  Jeff  drawings,  sixty  assist- 
ants are  employed  to  help  the  head  artist,  who  has  general 
charge  of  the  work. 

Talking  movies.  Finally,  we  have  the  talking  movies, 
which  consists  of  a  phonograph  and  a  moving-picture  machine 
working  in  unison.  At  first  thought  it  might  seem  a  simple 
thing,  to  start  them  both  at  the  same  time  and  let  them  run, 
but  as  a  matter  of  fact  it  has  proved  very  difficult  to  keep 
them  exactly  together.  In  recent  years  this  has  been  worked 
on  by  Edison  in  this  country  and  by  Gaumont  in  France. 

In  order  to  get  the  best  results,  it  is  necessary  that  the 
records  on  the  phonograph  be  taken  at  the  same  time  that 
the  camera  is  taking  the  pictures,  and  then  that  these  be 
reproduced  together. 

The  important  part  of  the  talking  movies  is  the  mechanism 
by  which  the  phonograph  and  moving-picture  machine  are 
kept  in  exact  unison.  In  some  of  the  first  machines  made, 
this  was  controlled  by  the  operator,  who  managed  both 
machines  by  hand.  A  dial  with  hands,  like  the  face  of  a 
clock,  was  provided  for  each  machine  and  indicated  the 
speed.  The  operator  watched  these  dials  and  tried  to  operate 
the  two  machines  so  that  the  hands  on  the  two  dials  main- 
tained the  same  position.  This  proved  a  very  difficult 
thing  to  do.  In  the  later  forms  the  machines  are  operated 
by  motors.  A  mechanism  is  so  arranged  that  the  operator 


MOVING  PICTURES  457 

has  to  watch  only  one  needle,  and  a  device  is  provided  so 
that  the  speed  of  the  motors  may  be  changed  until  the  two 
machines  work  in  unison.  This  has  now  been  perfected 
to  the  stage  where  it  works  very  satisfactorily,  and  these 
machines  are  now  found  in  many  of  our  large  cities. 

The  talking  movies  have  proven  successful  enough  so 
that  we  can  get  some  idea  of  their  possibilities  when  we  have 
seen  and  heard  renowned  men  and  women  from  distant  parts 
of  the  country,  sometimes  after  their  death.  It  will  be  a 
wonderful  thing  for  future  generations  to  be  able  to  see  and 
hear  the  great  men  and  women  of  to-day.  How  much  it 
would  be  worth  to  us  to-day  if  we  could  hear  the  voices  and 
see  the  actions  of  the  great  men  who  stand  out  conspicuous 
in  our  country's  history,  like  Grant  and  Lee,  Washington 
and  Lincoln ! 


SUPPLEMENTARY  QUESTIONS  FOR   CLASS  DISCUSSION 

1.  What  were  the  first  steps  taken  in  the  development  of 
the  moving  picture  ? 

2.  What  part  did  Thomas  Edison  play  in  the  development 
of  the  moving  picture  ? 

3.  What  was  the  relation  between  the  development  of  the 
movies  and  the  development  of  photography  ? 

4.  How  does  the  moving-picture  camera  work  ? 

5.  How  is  the  film  developed  and  the  positive  made? 

6.  How  are  the  pictures  thrown  on  the  screen  ? 

7.  What  peculiarity  of  the  action  of  the  eye  makes  the 
moving  picture  possible  ? 

8.  What    are    some    interesting    educational    applications 
made  of  the  movies? 

9.  What   uses   could   be   made  in  your  school   of   moving 
pictures  ? 

10.  How  is  the  animated  newspaper  managed? 

1 1 .  How  are  trick  pictures  produced  ? 

i«.    Watch  carefully  the  movies  you  attend  and  notice  what 


458  SCIENCE  OF  HOME  AND   COMMUNITY    - 

are  trick  pictures.     How  many  kinds  of  trick  pictures  can  you 
find? 

13.  Which  do  you  consider  the  most  interesting  trick  pictures  ? 

14.  What  are  the  special  advantages  of  the  talking  movies  ? 


REFERENCES 

Cressey,   Discoveries  and   Inventions  of  the    Twentieth   Century, 

E.  P.  Button  Co.,  New  York  City.     Pages  360-373. 
Dench,  Making  the  Movies,  Macmillan  Co.,  New  York  City. 
Doubleday,   Stories   of    Inventors,    Doubleday   Page   and    Co.r 

New  York  City.     Pages  113-131. 
Johnson,  Modern  Inventions,  F.  A.  Stokes  Co.,  New  York  City. 

Chap.  i. 
Maule,  Boys'  Book  of  New  Inventions,  Grosset  and  Dunlap  Co., 

New  York  City.     Chaps.  5-6. 
Welsh,  A-B-C  of  Moving  Pictures,  Harper  Bros.,  New  York 

City. 
Talbot,   Moving  Pictures,    How    They  Are   Made  and   Worked^ 

J.  B.  Lippincott  Co.,  Philadelphia. 


SECTION   E 
CONSERVATION  OF  COMMUNITY  RESOURCES 

CHAPTER  XXIX 
PROTECTION   OF   BIRDS 

1.  Why  should  birds  be  protected ? 

2.  What  is  being  done  to  protect  birds? 

There  are  in  nature  certain  forms  of  life  which  are  of  such 
great  value  to  man  that  they  should  be  protected.  Chief 
among  these  are  birds  and  forests.  In  order  to  protect 
these  adequately,  the  cooperation  of  all  concerned  is  neces- 
sary. The  work  of  just  one  individual  or  of  a  few  without 
help  from  others  will  be  of  little  avail. 

The  subject  of  bird  protection  will  be  treated  under  three 
headings:  first,  why  birds  should  be  protected;  second, 
against  what  they  need  to  be  protected;  and  third,  how 
birds  are  being  and  can  be  protected. 

Reasons  for  bird  protection.  Birds  should  be  protected 
on  account  of  both  their  esthetic  and  economic  value. 
Studies  of  the  food  habits  of  birds  show  that  birds  help  man 
in  three  ways :  by  eating  insect  pests ;  by  eating  weed  seeds ; 
and  by  eating  rodent  pests,  such  as  mice  and  rats. 

In  the  government  at  Washington  there  is  a  branch  of  the 
Department  of  Agriculture,  called  the  Bureau  of  Biological 
Survey.  The  purpose  of  this  branch  is  to  study  the  food 
habits  of  birds  and  to  determine  whether  these  birds  are 

459 


460  SCIENCE  OF  HOME  AND   COMMUNITY 

beneficial  or  injurious.  In  order  to  do  this,  specimens  of 
birds  are  collected  in  different  months  and  from  different 
states.  The  experts  at  Washington  open  the  stomachs  of 
these  birds  and  make  a  careful  study  of  their  contents. 
From  this  study  they  are  able  to  determine  what  food  the 
birds  have  been  eating.  So  far  the  Bureau  of  Biological 
Survey  has  examined  more  than  sixty  thousand  stomachs, 
comprising  over  four  hundred  species  of  birds. 

For  instance,  in  order  to  find  out  about  the  food  of  the 
robin,  1236  specimens  were  collected  in  different  months 
from  forty-two  states,  the  District  of  Columbia,  and  three 
Canadian  Provinces.  It  was  found  that  about  one  seventh 
of  the  robin's  food  was  made  up  pf  things  valuable  to  man, 
such  as  fruit  and  beneficial  insects,  one  third  was  composed 
of  injurious  insects,  and  about  one  half  was  made  of  neutral 
elements,  chiefly  wild  fruit. 

Birds  as  insect  destroyers.  These  studies  have  shown 
that  insects  form  the  chief  food  of  birds,  and  that  most  of 
these  insects  are  injurious  to  man  because  they  feed  upon 
the  crops  he  is  raising,  or  because  they  carry  diseases.  Birds 
help  man  because  they  keep  these  insects  down  to  such  a 
point  that  man  is  able  to  control  those  that  remain.  If  man 
were  to  be  deprived  of  the  services  of  the  birds,  insects  would 
increase  to  such  an  extent  that  man  would  have  a  terrible 
struggle  to  overcome  them. 

Amount  eaten  by  birds.  One  thing  that  makes  birds  so 
helpful  is  the  fact  that  they  devour  so  many  insects  in  the 
course  of  a  day.  Birds  watched  in  the  field  have  been  ob- 
served to  eat  from  two  to  ninety  insects  in  a  minute,  depend- 
ing on  the  bird  and  the  kind  of  insect.  In  the  studies  made 
by  the  Biological  Survey  it  was  found  that  a  single  stomach 
of  a  bird  contained  a  great  many  insects.  For  instance,  the 
stomach  of  a  grosbeak  was  found  to  contain  fourteen  potato 
beetles ;  a  crow  blackbird,  thirty  grasshoppers ;  and  a  flicker, 
five  thousand  ants. 


PROTECTION  OF  BIRDS  461 

It  was  also  found  that  a  single  species  of  bird  feeds  on  a 
great  many  kinds  of  insects.  For  example,  the  downy 
woodpecker  was  found  to  eat  forty-three  different  kinds  of 
insects ;  the  robin,  two  hundred  twenty- three  kinds ;  and  the 
night  hawk,  six  hundred  kinds. 

It  was  further  found  that  many  different  kinds  of  birds  feed 
upon  some  one  kind  of  insect.  For  example,  twenty-six  kinds 
have  been  found  to  feed  upon  the  potato  beetle,  thirty-six 
kinds  on  the  codling  moth  (the  caterpillar  of  which  is  the 
worm  of  wormy  apples),  eighty-eight  kinds  on  cutworms,  and 
one  hundred  twenty-eight  kinds  on  the  click  beetles  or  their 
larvae,  the  wireworms. 

Food  of  nestlings.  Nestling  birds  require  vast  amounts  of 
food  and  are  fed  frequently  during  the  day  beginning  at 
sunrise  and  continuing  till  sunset.  One  pair  of  house  wrens 
was  observed  to  feed  its  young,  two  hundred  and  thirty- 
eight  times  in  one  day.  During  the  two  weeks  these  young 
were  in  the  nest,  they  ate  from  four  thousand  to  five  thousand 
insects.  Observations  made  of  many  young  birds  show  that 
it  is  a  common  thing  for  birds  to  feed  their  young  two  hun- 
dred times  in  one  day,  or  about  once  every  four  minutes. 

One  man,  after  watching  a  pair  of  marsh  wrens  carrying 
grasshoppers  to  their  young,  estimated  that  the  grass- 
hoppers eaten  by  all  the  birds  in  eastern  Nebraska  in  one 
day  would  have  destroyed  about  $1700  worth  of  crops  had 
it  not  been  for  the  birds.  Another  man  estimates  that  the 
birds  of  New  York  State  destroy  annually  more  than  three 
million  bushels  of  injurious  insects. 

FIELD  EXERCISE  9 

Purpose.  To  see  how  many  times  nestling  birds  are  fed  in 
one  day. 

Directions.  A  nest  of  some  bird  should  be  located  that  can 
conveniently  be  watched.  The  class  may  be  divided  into  small 
groups,  and  each  group  assigned  to  watch  the  birds  for  a  cer- 


462  SCIENCE  OF  HOME  AND   COMMUNITY 

tain  length  of  time,  say  an  hour.  A  record  should  be  kept  of  the 
number  of  times  the  young  birds  are  fed,  and  if  the  sexes  can 
be  distinguished  either  by  color  or  song,  the  number  of  times  each 
parent  brings  food  should  be  recorded.  The  birds  feed  from 
sunrise  till  sunset,  and  if  there  are  not  enough  groups  to  watch 
them  all  day,  an  estimate  for  the  whole  day  may  be  made  from 
the  results  obtained  for  the  time  the  birds  are  watched. 

Number  of  insects  eaten.  It  is  possible  to  make  an  esti- 
mate of  the  number  of  insects  eaten  by  birds  east  of  the 
Mississippi  River.  A  census  has  been  made  of  the  number  of 
birds  found  here,  and  observations  have  been  made  of  the 
number  of  times  young  birds  are  fed.  On  this  basis  we  get 
an  estimate  of  ten  trillion  insects  as  the  number  eaten  by  the 
birds  each  summer  east  of  the  Mississippi  River.  If  these 
were  placed  an  inch  apart,  they  would  make  a  procession 
one  hundred  and  sixty  million  miles  long,  which  would  reach, 
to  the  sun  and  almost  back.  If  it  traveled  at  the  rate  of  one 
mile  a  minute,  it  would  take  three  hundred  years  to  pass  a  given 
point.  If  placed  one  inch  apart  each  way,  these  would  make 
a  sheet  that  would  completely  cover  the  state  of  Delaware. 

Birds  as  destroyers  of  weed  seeds.  A  second  way  in 
which  birds  help  man  is  in  eating  weed  seeds.  •  The  most 
valuable  birds  for  this  purpose  are  the  mourning  dove,  the 
bob  white,  and  the  native  sparrows.  Two  thirds  of  the 
entire  food  of  the  dove,  and  about  one  half  of  the  food  of 
the  bob  white  and  sparrows  is  composed  of  weed  seeds.  The 
red-winged  blackbird  has  been  known  to  eat  fourteen  kinds  of 
weed  seeds,  the  horned  lark  thirty-eight  kinds,  and  the  bob- 
white  one  hundred  and  twenty-nine  kinds.  A  single  bird 
eats  an  enormous  number  of  seeds.  In  a  single  stomach  of  a 
chipping  sparrow  have  been  found  one  hundred  and  fifty 
seeds  of  crabgrass,  and  in  that  of  a  Ipob white,  ten  thousand 
seeds  of  pigweed.  Professor  Beal  has  estimated  that  the 
tree  sparrows  in  the  state  of  Iowa  alone  consume  every  year 
eight  hundred  and  seventy-five  tons  of  weed  seeds. 


PROTECTION  OF   BIRDS 


463 


FIG.  182.  —  Four  common  seed-eating  birds. 
i,  Junco ;    2,  White-throated  sparrow ;  3,  Fox  sparrow ;   4,  Tree  sparrow. 


464  SCIENCE  OF  HOME  AND   COMMUNITY 

Most  of  the  work  of  eating  weed  seeds  is  done  between 
early  autumn  and  late  spring.  During  the  summer,  birds 
feed  largely  on  insects.  This  group  of  birds  is  beneficial 
then  in  two  ways,  in  eating  insects  and  in  eating  weed  seeds. 

Destroyers  of  rodent  pests.  Still  a  third  way  in  which 
birds  help  man  is  in  destroying  rodent  pests,  such  as  rats, 
mice,  and  ground  squirrels.  The  birds  which  are  helpful  in 
this  way  are  the  hawks  and  the  owls.  These  birds  have 
been  greatly  misjudged.  Because  a  few  hawks  destroy  some 
poultry,  the  .wrong  notion  has  got  abroad  that  all  hawks 
and  owls  are  injurious.  As  a  matter  of  fact  only  two  com- 
mon hawks,  Cooper's  hawk  and  the  sharp-shinned  hawk, 
are  injurious,  and  no  common  owl  is.  There  are  several 
hawks  which  may  occasionally  take  a  chicken;  but  this  is 
the  exception  and  it  is  made  up  many  times  by  the  good 
they  do.  About  ten  per  cent  of  the  species  of  hawks  and 
owls  are  injurious,  fifteen  per  cent  are  neutral,  and  seventy- 
five  per  cent  are  beneficial.  That  is,  more  than  seven  times 
as  many  species  are  beneficial  as  are  injurious. 

Eight  mice  have  been  found  in  the  stomach  of  a  single 
hawk.  It  seems  fair  to  suppose  that  a  hawk  or  owl  would 
destroy  one  thousand  mice  a  year.  It  has  been  estimated 
that  a  mouse  will  do  two  cents'  worth  of  damage  in  a  year, 
so  that  these  one  thousand  mice  would  do  twenty  dollars' 
worth  of  damage.  A  hawk  or  owl,  then,  may  be  said  to 
be  worth  twenty  dollars  a  year. 

Harm  done  by  birds.  A  little  harm  is  done  by  some 
birds.  Some  birds,  like  the  catbird  and  the  cedar  waxwing, 
feed  on  cultivated  fruit.  Other  birds,  such  as  the  English 
sparrow,  crow  blackbird,  and  crow,  feed  on  grain.  About 
one  half  of  this  is  waste  grain,  and  so  should  not  be  counted 
against  the  bird.  As  already  mentioned,  some  hawks  and 
owls  destroy  poultry.  The  worst  offender  is  Cooper's  hawk. 
The  sapsucker  does  damage  to  trees  by  drilling  holes. 
Sometimes  the  tree  is  killed,  but  the  chief  damage  is  due  to 


PROTECTION  OF  BIRDS  465 

the  fact  that  after  the  tree  is  cut  down  and  sawed  up  into 
lumber,  the  little  holes  formed  in  drilling  lower  the  value  of 
the  lumber.  Some  birds,  such  as  the  flycatchers  and  swal- 
lows, eat  beneficial  insects.  And  finally  some  birds  destroy 
other  valuable  birds.  More  than  half  of  the  food  of  the 
sharp-shinned  hawk  consists  of  small  valuable  birds. 

Summary.  We  may  summarize  briefly  by  saying  that 
birds  may  be  divided  into  three  groups :  injurious,  neutral, 
and  beneficial.  To  the  injurious  group  belong  four  common 
birds :  the  English  sparrow,  the  sapsucker,  Cooper's  hawk, 
and  the  sharp-shinned  hawk.  To  the  neutral  group,  in 
which  the  harm  and  good  about  balance,  belong  five  com- 
mon birds :  the  catbird,  the  cedar  bird,  the  crow,  the  crow 
blackbird,  and  the  blue  jay.  The  remaining  common  birds 
are  beneficial.  If  we  take  one  hundred  as  the  number  of 
species  of  common  birds  that  might  be  found  in  a  locality, 
they  would  be  divided  as  follows :  injurious,  four  per  cent ; 
neutral,  five  per  cent ;  beneficial,  ninety-one  per  cent.  To 
state  the  matter  more  briefly,  four  per  cent  do  more  harm 
than  good,  and  ninety-one  per  cent  do  more  good  than 
harm ;  that  is,  for  every  species  of  harmful  bird,  there  are 
twenty-two  species  of  beneficial  birds. 

Mr.  H.  W.  Henshaw,  chief  of  the  Bureau  of  Biological 
Survey,  writes  in  a  recent  article :  "  What  would  happen 
were  birds  exterminated,  no  one  can  foretell  with  absolute 
certainty,  but  it  is  more  than  likely,  nay,  it  is  almost  certain 
that  within  a  limited  time  not  only  would  successful  agri- 
culture become  impossible,  but  the  destruction  of  the  greater 
part  of  vegetation  would  follow.  It  is  believed  that  a 
permanent  reduction  in  the  number  of  our  .birds,  even  if 
no  species  are  exterminated,  will  inevitably  be  followed  by 
disastrous  consequences." 

The  food  habits  of  a  few  common  birds  are  briefly  sum- 
marized in  the  following  table,  which  is  based  on  the  reports 
of  the  Bureau  of  Biological  Survey. 

2H 


466  SCIENCE  OF  HOME  AND   COMMUNITY 

TABLE  OF  FOOD  OF  A  FEW  COMMON  BIRDS 


NAME  OF  BIRD 

To  BIRD'S  CREDIT 

To  BIRD'S  DISCREDIT 

Insect 
Pests 

Weed 
Seeds 

Total 
Credit 

Culti- 
vated 
Fruit 

Grain 

Benefi- 
cial 
Insects 

Total 
Debit 

per  cent 

Per  cent 

per  cent 

Per  cent 

Per  cent 

per  cent 

per  cent 

Crow  blackbird     .     . 

19 

4 

23 

3 

22 

6 

31 

Red-winged       black- 

bird       

20 

57 

77 



7 

'  5 

12 

Bluebird  

47 

47 



9 

9 

Bob  white     .... 

10 

50 

60 



5 

5 

Cardinal       .... 

2A 

36 

60 



4 

2 

6 

Catbird  

"T 

12 

O 

12 

19 

3 

22 

Cedar  bird  .... 

10 

— 

IO 

13 

— 

13 

Cowbird       .... 

2O 

60 

80 

8 



g 

Crow  

13 

13 

4 

25 

2 

31 

Cuckoo    

88 

— 

88 



Mourning  dove 

— 

64 

64 

— 

8 



8 

Flicker    

55 

55 

— 

i 

2 

3 

Crested  flycatcher 

70 

— 

70 

— 

— 

3 

3 

Least  flycatcher    . 

52 

— 

52 

— 

— 

13 

13 

Rose-breasted     gros- 

beak     

45 

16 

61 

— 

2 

5 

7 

Blueiay                   . 

10 



IQ 

2 

q 

4- 

IS 

Tunco 

s 

17 

62 

*x 
70 

y 

A 

*T 

<J 
A 

Kingbird      .... 

A  / 
50 

/  :7 

50 



*T 

13 

T^ 

13 

Horned  lark      .     .     . 

15 

64 

79 



2 

2 

Meadowlark     .     .     . 

56 

7 

63 



3 

12 

15 

Baltimore  oriole    .     . 

58 

58 







Wood  pewee     .     .     . 

56 

— 

56 



— 

II 

II 

Phoebe     

51 

— 

5i 



•  —  - 

IO 

10 

Robin      

33 

— 

33 

8 

— 

6 

14 

Chipping  sparrow 

28 

53 

81 

— 

2 

i 

3 

English  sparrow    . 

— 

24 

24 

— 

37 

— 

37 

Field  sparrow  . 

30 

40 

70 

— 

4 

4 

8 

Song  sparrow  . 

18 

50 

68 

— 

2 

2 

4 

Vesper  sparrow 
Brown  thrasher     .     . 

22 

33 

42 

64 
33 

8 

6 

3 

2 

8 

8 
19 

Wood  thrush    .     .     . 

38 

— 

38 

4 

— 

2 

6 

Downy  woodpecker  . 

69 

— 

69 

i 

2 

3 

Hairy  woodpecker    . 

72 

— 

72 

— 

i 

I 

2 

House  wren     .     .     . 

69 

_ 

69 

6 

6 

In  putting  down  the  amount  of  grain  eaten,  the  per  cent 
of  waste  grain  has  been  subtracted  from  the  total  per  cent 


PROTECTION  OF  BIRDS 


467 


of  gram  eaten,  thus  leaving  only  that  portion  which  can  be 
considered  to  the  bird's  discredit.  The  figures  represent  the 
per  cent  of  the  total  food  for  the  year  that  any  item  forms. 


LABORATORY  EXERCISE  36 

Purpose.     To  study  the  food  habits  of  some  common  birds. 

Directions.  From  a  study  of  the  above  food  chart  answer 
the  following  questions.  Copy  the  following  table  in  your 
notebook  and  write  in  it  the  answers  to  questions  1-6  by 
writing  the  names  of  the  birds  in  the  proper  column  and  the 
per  cents  in  order,  the  largest  first. 


BENEFICIAL  EFFECTS 

INJURIOUS  EFFECTS 

Insect  Pests 
(So  %  or 
over) 

Weed  Seeds 
(So  %  or 
over) 

Weeds  and 
Insects 
(20%  of 
each) 

Grain 
(10%  or 
over) 

Cultivated  Fruit 
(10%  or  over) 

Beneficial  Insects 
(10  %  or  over) 

1.  Which  birds  are  specially  valuable  as  destroyers  of  insect 
pests  (50%  or  over)  ? 

2.  Which    are    especially   valuable    as   destroyers   of    weed 
seeds  (50%  or  over)  ? 

3.  Which  are  valuable  for  destroying  both  insect  pests  and 
weed  seeds  (20%  or  more  of  each)  ? 

4.  Which    birds    feed    to    any   extent    on    grain    (10%   or 
more)  ? 

5.  Which  birds  feed  to  any  noticeable  extent  on  cultivated 
fruit  (10%  or  over)? 

6.  Which  birds   feed    to   any  extent   on   beneficial    insects 
(10%  or  over)? 

7.  Which  of  those   birds  that  feed  on  grain  or  cultivated 
fruit  destroy  enough  insect  pests  or  weed  seeds  to  balance  the 
harm  done  ? 


468  SCIENCE  OF  HOME  AND   COMMUNITY 

8.    Copy  the  following  table  and  write  in  it  the  answers  to 
questions  9,  10,  n. 


BIRDS  DISTINCTLY  INJURIOUS 

BIRDS  NEUTRAL 

BIRDS  DISTINCTLY  BENEFICIAL 

9.  Which  birds  on  the  chart  do  very  much  more  harm  than 
good,  that  is,  have  the  debit  column  fifty  per  cent  or  more 
greater  than  the  credit  column?  Put  these  in  the  first  column. 

10.  With  what  birds  are  the  good  and  harm  done  about  the 
same,  that  is,  not  more  than  ten  per  cent  difference  ?     Put  these 
in  the  second  column. 

11.  What  birds   are  decidedly  beneficial,  that  is,   have  the 
credit  column  fifty  per  cent  or  more  greater  than  the  debit 
column?     Put  these  in  the  last  column. 

12.  Arrange  the  birds  according  to  the  ratio  between  the 
good  and  harm  done.     Place  the  cuckoo  and  oriole  at  the  head 
of  the  list.     For  the  others  divide  the  percentage  of  good  done 
by  the  percentage  of  harm  done.     For  example,  for  the  chipping 
sparrow  divide  81  by  3  (27).     Do  the  same  with  the  others  and 
arrange  them  in  order,  the  bird  with  the  largest  number  first. 
Which  five  birds  stand  first  in  the  list  ?     Which  five  last  ? 

13.  (Optional.)     If  you  wish  you  may  make  a  chart  from 
this  table  similar  to  the  one  in  Figure  183.     This  chart  is  to  repre- 
sent the  ratio  between  the  good  and  harm  done.     Let  one  inch 
represent  5.     Then  for  the  chipping  sparrow  draw  a  line  5|  (-2/) 
inches  long.     In  a  similar  way  draw  lines  for  the  other  birds, 
arranging  them  in  the  order  of  the  length  of  the  line,  the  longest 
first.     Make  the  lines  for  the  cuckoo  and  oriole  two  inches  and 
one  inch,  respectively,  longer  than  that  for  the  chipping  sparrow. 

FIELD  EXERCISE  10 

Purpose.  To  learn  what  beneficial  birds  are  common  in  your 
locality. 

Directions.  I.  In  order  to  find  what  birds  are  common  in 
the  locality,  field  trips  may  be  taken  with  the  purpose  of  identify- 


PROTECTION   OF   BIRDS 


469 


10ft       20*      30*      40*      60* 


ft?      80*      90* 


Cuckoo f~~ 

Chipping  Sparrow. L_ 

Red-winged  Blackbird 

House  Wren 

Downy  Woodpecker C 

Song  Sparrow. I 

Mourning  Dove 

Meadowlark  

Rose-breasted  Grosbeak. 
Bobwhite  ... 

Baltimore  Oriole 

Flicker, 

JPhoebe... 
Kingbird 
Bluebird 

Wood  Thrush 

Brown  Thrasher_ 
Robin 


388* 


English  .Sparrow.. 
Crow  Blackbird™ 


2224$ 


174* 


Red-headed  Woodpecker. 

Blue  Jay. 

Crow 

Catbird 

Cedar  Waxwiag 

FIG.  183.  —  Food  Chart  of  25  Common  Birds. 

The  upper  black  bar  represents  food  to  the  bird's  discredit  (grain,  cultivated  fruit, 
beneficial  insects) ;  the  lower,  food  to  the  bird's  credit  (dHHH  injurious  insects ; 
EiftWftWJ  weed  seeds).  The  length  of  line  is  based  on  the  percentage  that  these 
foods  form  of  the  bird's  total  food,  as  determined  by  the  Bureau  of  Biological 
Survey. 


470 


SCIENCE   OF  HOME  AND    COMMUNITY 


ing  as  many  birds  as  possible.  The  spring  is  the  best  time  to 
study  birds  in  the  field.  For  each  bird  seen,  a  record  should  be 
made  in  the  field  of  some  of  the  following  points :  i.  size  (com- 
pare with  robin  or  English  sparrow) ;  2.  general  colors  above 
and  below;  3.  more  detailed  description  of  colors  found  on  head, 
back,  tail,  wings,  and  breast ;  4.  any  peculiarity  of  flight ;  5.  char- 
acteristics of  song;  6.  the  most  conspicuous  field  marks  by 
which  the  bird  may  be  identified  again. 

2.  After  returning  from  the  field  look  up  the  economic  stand- 
ing of  each  bird  seen  by  referring  to  the  food  chart  on  page  466. 

Enemies  of  birds.  Having  shown  that  birds  are  of  great 
value  to  man,  we  may  next  inquire  what  are  the  enemies 

against  which  birds 
need  to  be  protected. 
The  chief  enemies  of 
our  common  song 
birds  are  the  cat  and 
the  English  sparrow. 
Cats.  The  cat 
does  a  great  deal  of 
harm  during  the 
nesting  season,  by 
feeding  upon  young 
birds  while  they  are 
in  the  nests  and  just 
after  they  leave  the 
nest.  Oftentimes 
also,  adult  birds  are  caught  while  on  the  nest  or  while  de- 
fending the  young.  Most  of  the  harm  is  done  in  the  early 
morning.  Most  bird  students  agree  that  the  cat  is  the  worst 
enemy  of  our  song  birds. 

A  number  of  observations  have  been  made  of  the  number 
of  birds  killed  by  a  cat  in  a  single  season.  One  cat  was  seen 
to  kill  fifty-eight  birds  in  a  season.  (See  Fig.  184.)  Cats 
have  frequently  been  observed  to  kill  two  or  three  birds  in  a 


FIG.  184.  —  Cat  with  robin.    This  cat  was  seen  to 
kill  58  birds  in  one  season. 


PROTECTION  OF  BIRDS  471 

day  and  one  cat  has  been  observed  to  kill  more  than  ten  birds 
in  one  day.  Mr.  Forbush  estimates  that  a  mature  cat  in  good 
hunting  grounds  kills  fifty  birds  each  year.  Dr.  Fisher  esti- 
mates that  cats  destroy  annually  3,500,000  birds  in  the  state 
of  New  York  alone.  It  has  been  estimated  that  in  the  United 
states  east  of  the  Mississippi  River  cats  kill  annually  from 
seventy-five  to  one  hundred  million  birds,  mostly  nestlings. 

Bird  students  generally  agree  that  one  of  the  first  steps 
necessary  for  the  control  of  the  cat  is  to  require  a  license , 
similar  to  that  now  required  for  dogs.  This  would  lead 
people  to  keep  fewer  cats  and  to  take  better  care  of  those 
which  they  licensed.  At  the  same  time  provision  should  be 
made  for  the  disposition  of  stray  homeless  cats  in  some 
humane  way.  People  who  keep  cats  should  see  that  during 
the  nesting  season,  the  cats  are  kept  shut  up  during  the  night 
and  early  morning  and  that  they  are  well  fed. 

English  sparrow.  The  English  sparrow  is  injurious  to 
other  birds  both  directly  and  indirectly.  It  attacks  other 
birds  and  breaks  up  their  nests,  destroying  their  eggs  and 
young.  Indirectly,  it  is  specially  injurious  to  birds  that 
nest  in  cavities,  such  as  the  wrens,  bluebirds,  and  martins. 
It  is  so  persistent  in  taking  the  nesting  sites  of  these  birds 
that  gradually  they  leave  localities  where  the  sparrows  are 
common. 

Sparrows  may  be  controlled  in  three  ways :  by  shooting, 
by  trapping,  and  by  poisoning.  In  sections  where  shooting 
is  allowed,  this  may  prove  an  effective  means  if  persisted  in. 
In  cities,  however,  shooting  is  not  allowed.  Trapping  is  a 
very  effective  means  and  may  be  used  anywhere.  If  native 
birds  are  caught,  they  can  be  released  without  any  injury. 
Under  certain  circumstances,  poisoning  may  be  used;  but 
as  there  is  danger  that  valuable  birds  may  be  poisoned,  this 
method  can  be  used  only  where  sparrows  alone  are  found. 

Man  as  an  enemy  of  birds.  Man  himself  is  one  of  the 
bird's  worst  enemies.  In  years  past  when  men  have  hunted 


472  SCIENCE  OF  HOME  AND   COMMUNITY 

birds  to  sell  in  the  market,  enormous  numbers  have  been 
killed,  and  our  game  birds  have  greatly  decreased  in  num- 
bers. In  the  case  of  the  passenger  pigeon,  the  birds  have 
become  extinct.  Formerly  these  birds  existed  in  tremendous 
numbers,  single  flocks  being  seen  which  were  estimated  to 
contain  two  billion  birds.  These  birds  were  slaughtered 
for  market  in  such  numbers  that  they  gradually  became 
scarcer,  until  to-day  not  a  single  living  passenger  pigeon  is 
left.  To-day,  however,  there  is  very  little  hunting  for 
market. 

Another  reason  for  the  marked  decrease  in  game  birds 
has  been  excessive  shooting  by  sportsmen.  It  is  estimated 
that  each  year  an  army  of  about  five  million  men  and  boys 
go  out  in  the  fall  to  shoot  game  birds.  The  open  season  has 
been  so  long  and  the  bag  limit  so  high,  that  the  birds  have 
gradually  decreased.  If  the  sportsmen  were  few,  the  danger 
would  not  be  so  apparent;  but  there  is  such  an  enormous 
number  of  them  that  even  when  all  keep  within  the  limits 
of  the  law,  it  is  easy  to  see  that  large  numbers  of  birds  must 
be  killed,  and  that  many  species  may  disappear  altogether 
unless  they  are  given  better  protection. 

In  years  past,  many  birds  have  been  killed  for  millinery 
purposes.  As  a  result  some  species,  like  the  egrets,  have 
become  very  scarce  and  even  almost  extinct.  But  on  the 
whole  at  the  present  time  very  few  birds  are  being  killed  for 
their  plumage. 

Bird  protection.  Having  shown  that  birds  are  of  great 
value  to  man,  and  that  these  have  certain  enemies,  we  may 
next  ask  what  is  being  done  and  can  be  done  to  protect  birds 
from  these  enemies. 

Audubon  Societies.  The  most  important  agency  in  this 
country  in  the  cause  of  bird  protection  is  the  National 
Association  of  Audubon  Societies.  At  first,  separate  state 
Audubon  Societies  were  formed.  Later,  this  national 
organization  was  formed,  the  state  societies  cooperating  with 


PROTECTION  OF  BIRDS 


473 


it.  The  work  of  the  national  association  has  been  extended 
in  many  lines,  including:  i.  legislation;  2.  warden  work; 
3.  publications;  4.  Junior  Audubon  classes;  and  5.  field 
agents. 

The  association  has  been  active  in  getting  proper  bird 
laws  passed.  A  number  of  years  ago  a  model  bird  law  for 
song  birds  was  proposed;  this  has  now  been  adopted  in 


FIG.  185.  —  Nest  and  nestlings  of  little  green  herons. 

forty  states.  Laws  giving  better  protection  to  game  birds 
have  been  passed  as  a  result  of  the  activities  of  this  asso- 
ciation. 

Many  water  birds  nest  together  in  large  colonies  and  the 
association  hires  wardens  to  protect  these  birds  during  the 
nesting  season.  It  was  estimated  that  during  the  season 
of  1913  about  two  million  birds  were  protected  in  this  way. 


474  SCIENCE  OF  HOME  AND   COMMUNITY 

The  association  publishes  a  magazine,  called  Bird  Lore, 
which  contains  illustrated  articles  and  notes  on  birds.  A 
large  number  of  colored  pictures  and  leaflets  are  published, 
amounting  to  four  million  copies  annually.  These  pictures 
are  sold  for  three  cents  each. 

During  the  past  five  or  six  years,  a  great  work  has  been 
done  in  schools  through  the  organization  of  bird  clubs 
among  the  children.  The  work  has  grown  in  importance 
each  year,  and  during  1917  there  were  organized  11,935 
classes,  including  261,654  members. 

A  number  of  lecturers,  called  field  agents,  are  employed, 
who  devote  their  time  to  lecturing  on  birds  and  aiding  the 
work  of  the  association  in  other  ways. 

There  are  now  state  Audubon  societies  in  thirty-seven 
states  and  in  the  District  of  Columbia.  These  cooperate 
with  the  national  association,  and  also  carry  on  other  lines 
of  work  independently. 

Bird  protection  by  governments.  Much  progress  has  been 
made  in  this  country  in  protecting  birds  by  state  laws. 
The  tendency  has  always  been  to  give  more  complete  pro- 
tection to  birds  in  the  enactment  of  these  state  laws.  During 
recent  years  the  national  government  has  taken  important 
steps  to  protect  birds,  recognizing  the  fact  that  since  birds 
migrate  from  one  state  to  another,  their  protection  is  a 
matter  for  the  national  government. 

In  1913  Congress  passed  the  migratory  bird  law.  In 
accordance  with  this,  all  migratory  birds  that  pass  from  one 
state  to  another  are  given  some  degree  of  protection  by  the 
national  government.  The  exact  regulations  were  worked 
out  by  a  committee  of  experts  from  the  Bureau  of  Biological 
Survey.  These  regulations  are  the  most  important  scientific 
document  ever  issued  in  the  cause  of  bird  protection. 

Migratory  birds  are  first  divided  into  two  groups,  the 
insectivorous  birds  and  the  game  birds.  Insectivorous 
birds  are  protected  during  all  the  year.  Some  game  birds 


PROTECTION  OF  BIRDS  475 

which  are  becoming  scarce,  such  as  most  of  the  shore  birds, 
were  given  complete  protection  for  five  years,  until  1918. 
The  other  game  birds  are  given  protection  for  about  nine 
months,  an  open  season  of  about  three  months  being  allowed 
in  the  autumn.  In  1918  this  migratory  bird  law  was  re- 
placed by  the  bird  treaty  with  Canada.  This  grants  the 
same  sort  of  protection  provided  by  the  migratory  bird  law, 
but  it  is  more  satisfactory  and  comprehensive. 

Another  thing  the  government  has  been  doing  to  protect 
birds  has  been  to  set  aside  bird  reservations,  where  birds 
receive  complete  protection  at  all  times.  The  first  reser- 
vation was  set  aside  in  1903.  Since  that  time  others  have 
been  added  till  there  were  sixty-nine  in  1915. 

Bird  clubs.  Other  agencies  which  have  been  active  in 
protecting  birds  are  the  bird  clubs  which  have  been  formed 
in  various  parts  of  the  country.  At  the  present  time  there 
are  several  hundred  of  these  with  adult  membership,  besides 
many  children's  clubs.  The  best  known  of  these  clubs  is 
the  Meriden  Bird  Club,  in  New  Hampshire.  A  large  per 
cent  of  the  population  of  this  little  village  are  members  of 
this  club.  Special  pains  have  been  taken  to  attract  and  to 
protect  birds  here  both  in  summer  and  in  winter,  with  the 
result  that  many  birds  are  found  here.  The  English  sparrow 
has  been  completely  driven  away  from  this  village.  A 
special  bird  sanctuary  of  thirty- two  acres  has  been  set  aside, 
and  special  efforts  are  made  to  attract  the  birds  there. 

Other  similar  clubs  have  been  formed  in  various  parts  of 
the  country.  Besides  the  Junior  Audubon  classes,  to  which 
reference  has  been  made,  there  is  another  bird  club  composed 
chiefly  of  children,  known  as  the  Liberty  Bell  Bird  Club. 
This  has  a  membership  of  more  than  700,000.  All  the  bird 
clubs  of  this  country  have  a  total  membership  of  about  one 
million. 

What  remains  to  be  done.  The  work  now  being  done  by 
these  various  protective  agencies  should  be  continued  and 


476  SCIENCE  OF  HOME  AND   COMMUNITY 

progress  should  be  made  along  other  lines.  Perhaps  the 
chief  needs  are  the  enforcement  of  the  existing  laws,  further 
protection  of  game  birds  from  sportsmen  by  more  stringent 
laws,  shortening  trie  open  season,  and  reducing  the  number 
of  species  that  may  be  shot.  To  protect  our  song  birds, 
steps  should  be  taken  to  control  the  cat  and  the  English 
sparrow.  In  the  cold  northern  states  birds  may  be  fed  in 
winter.  Every  person  can  do  something  to  help  protect 
the  birds. 

COMMUNITY  PROJECT  6 

Purpose.  To  see  what  the  class  can  do  to  help  protect 
the  valuable  birds  found  in  the  locality. 

Directions.  I.  Form  a  bird  club.  One  way  to  protect  birds 
is  to  form  a  bird  club.  It  may  be  a  club  composed  of  just  the  mem- 
bers of  the  class  or  the  club  may  be  open  to  any  one  in  the 
school  or  in  the  community.  One  of  the  best  ways  is  to  organize 
an  Audubon  Club.  Write  to  the  National  Association  of  Audu- 
bon  Societies,  1974  Broadway,  New  York  City,  for  particulars. 
Good  suggestions  on  forming  bird  clubs  are  found  in  the  last 
chapter  of  Baynes*  Wild  Bird  Guests,  published  by  E.  P.  Button 
Co.,  New  York  City.  For  suggestions  as  to  what  may  be  done 
by  the  club,  see  Chapter  17,  in  Tratton'sBird  Friends,  published 
by  Houghton  Mifflin  Co. 

2.  Build  bird  houses  to  put  up  in  the  city  parks.      See    the 
official  who  has  charge  of  the  parks  and  secure  permission  to 
put  up  bird  houses  in  the  parks.     The  class  may  divide  itself 
into  four  committees :  one  to  look  after  the  building  of  houses 
for  small  birds  like  the  wren ;  a  second  to  look  after  houses  for 
medium-sized   birds  like  the   bluebird;   a  third   to  look  after 
houses  for  large  birds  like  the  flicker ;  and  a  fourth  committee 
to  look  after  building  open  houses  for  birds  like  the  robin  and 
phoebe.     Care  should  be  taken  that  the  houses  are  put  up  in 
the  most  desirable  locations,  as  far  as  possible  in  the  open. 

3.  Feed  the  winter  birds.     During  the  winter,   many  birds 
like  the  bobwhite  perish  for  lack  of  food.     Provide  food  in  the 
parks  and  at  feeding  stations  in  the  country.     The  girls  in  the 


PROTECTION  OF  BIRDS  477 

class  may  help  in  securing  the  foods  and  the  boys  may  dis- 
tribute it.  Read  pages  129-136  in  Baynes'  Wild  Bird  Guests  for 
suggestions. 


SUPPLEMENTARY  QUESTIONS  FOR  CLASS  DISCUSSION 

1.  In  which  way  do  you  think  birds  do  more  good,  in  eating- 
weed  seeds  or  in  eating  injurious  insects? 

2.  What  can  you  say  regarding  the  amount  of  food  that 
birds  eat? 

3.  In  what  ways  may  some  birds  be  harmful? 

4.  Which  is  greater,  the  good  or  harm  done  by  hawks  and 
owls? 

5.  What  are  the  chief  enemies  of  song  birds? 

6.  In  what  ways  is  man  an  enemy  of  the  birds  ? 

7.  What  can  be  done  to  protect  birds  from  the  English 
sparrow  ? 

8.  What  can  be  done  to  protect  birds  from  the  cat? 

9.  What  is  the  National  Association  of  Audubon  Societies 
doing  to  protect  birds  ? 

10.  What  is  the  national  government  doing  to  protect  birds? 

1 1 .  What  can  you  do  to  protect  birds  ? 

12.  Look  up  the  laws  of  your  state  regarding  both  the  song 
and  the  game  birds. 

13.  Find  out  what  organizations  in  your  locality  and  state  are 
interested  in  bird  protection.     What  are  they  doing? 

REFERENCES 

Baynes,  Wild  Bird  Guests,  E.  P.  Button  Co.,  New  York  City. 
Trafton,  Bird  Friends,  Houghton  Mifflin  Co.,  Boston. 


CHAPTER  XXX 

SHADE  TREES  AND   FORESTS 

1.  What  care  should  be  given  the  shade  trees 
of  your  town  ? 

2.  Why  should  our  forests  be  conserved? 

3.  What  is  the  government  doing  to  conserve 
our  forests  ? 

Kinds  of  shade  trees.  Shade  trees  are  essential  to  make 
the  streets  of  a  town  attractive.  A  town  without  trees  is  a 
barren-looking  place.  In  the  selection  of  trees  for  street 
planting  those  species  should  be  selected  which  are  long- 
lived.  Among  the  best  trees  for  this  purpose  are  the  Ameri- 
can elm,  sugar  maple,  linden,  red  oak,  sycamore,  hackberry, 
Norway  maple,  and  red  maple.  These  should  be  planted 
at  such  distances  that  they  will  not  be  crowded  when  mature. 
This  distance  varies  from  thirty  feet  for  trees  like  the  catalpa 
to  fifty  feet  for  the  white  elm.  The  mistake  is  often  made  of 
planting  the  trees  too  close  together.  In  order  to  get  quicker 
results,  temporary  plantings  of  rapid-growing  trees,  such 
as  box  elder  and  white  maple,  may  be  made  between  the 
long-lived  trees.  When  these  rapid-growing  trees  have 
reached  such  a  height  as  to  interfere  with  the  other  trees, 
they  should  be  cut  down. 

Trees  are  attractive  in  the  winter  as  well  as  in  the  sum- 
mer. At  this  time  the  framework  is  more  easily  seen  than 
when  the  foliage  is  on  the  tree.  Many  trees  are  ornamental 
on  account  of  the  beauty  of  their  branches.  A  close  study 
of  the  twigs  shows  conspicuous  markings  by  means  of  which 

478 


SHADE  TREES   AND   FORESTS 


479 


the  trees  can  be  identified  as  easily  as  by  their  leaves  in  the 
summer. 

Planting  the  tree.     Trees  may  be  transplanted  either  in 
the  spring  or  fall,  except  in  the  extreme  northern  sections, 


Sour  Gum. 


White  birch. 


Wild  plum.  Wild  thorn-apple. 

FIG.  186.  —  Trees  in  winter,  showing  the  beauty  and  variety  of  their  branches. 

where  it  is  safer  to  plant  in  the  spring.  One  of  the  chief 
things  to  consider  in  transplanting  a  tree  is  to  reduce  the 
amount  of  water  given  off  by  the  leaf  to  the  point  where  the 
roots  can  supply  the  amount  lost  by  the  leaves.  When  a 
tree  is  dug  up  in  the  nursery  or  woods,  a  part  of  the  root 


SCIENCE  OF  HOME  AND   COMMUNITY 


system  is  left  in  the  ground,  and  enough  of  the  branches 
should  be  trimmed  off  to  correspond  with  this  loss  of  roots. 

It  is  safer  to  trim  off  too  much 
than  too  little.  A  severe  prun- 
ing is  always  safest. 

It  is  important  that  the  hole 
for  the  tree  should  be  dug  large. 
Many  people  err  in  making  the 
hole  too  small.  It  should  be 
dug  both  deep  and  broad  so  as 
to  be  larger  than  the  root  ex- 
panse. The  purpose  of  this  is 
to  give  the  newly 
formed  roots  con- 
tact with  a  soft, 
freshly  dug  soil. 
The  tree  should 
be  set  a  little 
deeper  than  it 
stood  in  the  nurs- 
ery. When  filling 
the  hole  the  soil 

should  be  trampled  down  firmly  to  make  sure 
that  the  soil  comes  in  contact  with  the  roots. 
At  the  surface  a  layer  of  loose  soil  should  be 
left  for  a  mulch. 

To  protect  the  tree  from  mechanical  injuries, 
it  should  be  surrounded  by  a  guard.  A  very 
effective  one  may  be  made  of  wire  cloth  with 
a  one-inch  mesh.  This  should  be  about  six 
feet  high  and  twenty  inches  wide  so  as  to 
encircle  the  tree. 

Care  of  shade  trees.     Pruning.     During  the 
tree's  growth  some  pruning  may  be  necessary  to  preserve 
the  symmetry  of  the  tree  or  for  other  reasons.     In  cutting 


FIG.  187.  — Twig  of  horse-chestnut. 


FIG.  i&8.— Lath 
tree  guard. 


SHADE  TREES  AND   FORESTS 


481 


off  a  branch  two  things  should  be  kept  in  mind ;  first,  to 
cut  in  such  a  way  that  the  branch  will  not  split  off  a  piece 
from  the  main  stem ;  and  second,  to  leave  the  wound  favor- 
able for  healing.  To  prevent  splitting,  the  limb  should  first 
be  sawed  half  way  through  from  the  under  side  about  six 
inches  from  the  main  stem,  and  then  cut  halfway  through 
from  the  upper  side  about  seven  inches  from  the  main  stem. 


FIG.  189.  —  The  wrong  way  to  cut 
off  a  branch. 


FIG.  190.  —  Tht;  -i-,uL  way  to  cut 
off  a  branch. 


This  allows  the  branch  to  drop  off.  The  remaining  stub 
should  then  be  cut  off.  This  final  cut  should  be  made  paral- 
lel to  the  main  stem  and  close  to  it,  instead  of  at  right  angles 
to  the  branch  that  is  being  cut,  as  is  so  often  done. 

If  a  stub  is  left  it  hinders  the  healing  of  the  wound  and 
offers  opportunity  for  disease  spores  to  enter.  These 
spores  grow  and  there  forms  a  branching  root -like  mass 
which  absorbs  food  from  the  tree  and  thus  injures  it.  The 
large  fruiting  bodies  of  these  fungi  are  often  seen  projecting 
2r 


482  SCIENCE  OF  HOME  AND   COMMUNITY 

from  wounds  in  trees.  The  cut  should  be  treated,  unless 
it  is  one  of  a  small  branch  two  inches  or  less,  with  coal  tar 
or  paint,  the  tar  being  preferable.  If  the  wounds  are  not 
thus  treated,  the  wood  cracks  and  furnishes  a  resting  place 
for  the  spores  of  disease-producing  fungi.  In  the  case  of 
large  wounds  this  treatment  should  be  renewed  every  two 
or  three  years.  If  the  proper  care  has  been  given,  in  the 
course  of  a  few  years  the  wound  will  be  covered  by  the 
growth  of  the  bark  around  it. 

Tree  surgery.  It  frequently  happens  that  large  cavities 
appear  in  some  part  of  the  tree  and  threaten  the  existence  of 
the  tree.  Tree  surgery  is  the  name  given  to  the  methods  now 
used  to  treat  these  cavities.  The  principles  involved  are 
very  similar  to  those  underlying  the  filling  of  teeth.  First, 
all  decayed  and  diseased  wood  must  be  removed  from  the 
cavity.  This  is  done  by  means  of  special  chisels  made  for 
the  purpose.  Second,  the  cut  surfaces  are  sterilized  in  order 
to  kill  any  germs  of  disease  or  decay  that  may  be  present. 
This  is  done  by  painting  with  creosote.  Third,  the  cut  sur- 
faces are  waterproofed  by  painting  with  coal  tar.  Fourth,  the 
cavities  are  filled  with  cement.  In  large  cavities  the  cement 
is  put  in  by  sections  separated  by  tar  paper,  to  prevent  the 
cracking  of  the  cement  by  the  bending  of  the  tree  in  the  wind. 
The  edge  of  the  cement  is  shaped  to  meet  the  wood  so  that 
it  stands  at  the  level  of  the  cambium  layer,  which  grows  out 
over  the  cement  and  in  time  may  cover  it  completely. 

Some  trees  bear  large  branches  at  such  angles  that  there  is 
danger  of  their  splitting  down  at  the  crotch.  These  may  be 
guyed  by  means  of  bolts  and  chains.  Holes  are  bored  through 
the  branches  and  the  bolts  inserted.  If  the  branches  are 
near  together,  one  bolt  may  pass  through  both  limbs.  If 
too  far  apart  for  this,  a  bolt  with  a  hook  is  passed  through 
each  branch  and  these  hooks  connected  by  a  chain.  The 
method  sometimes  used  of  passing  bands  of  iron  or  wires 
around  the  branch  girdles  it  and  injures  the  tree. 


SHADE  TREES   AND   FORESTS  483 

Miscellaneous  injuries.  Shade  trees  are  subject  to  injury 
from  a  number  of  causes  due  largely  to  man's  carelessness. 
Chief  among  these  are  gas  escaping  from  the  mains,  the 
regrading  of  streets,  the  hitching  of  horses  to  trees,  and  the 
trimming  of  trees  to  make  way  for  telephone  and  electric 
wires.  Sometimes  whole  rows  of  trees  may  slowly  die  be- 
cause the  gas  escapes  from  the  pipes  and  reaches  the  roots. 
This  may  be  avoided  by  requiring  the  gas  company  to  lay 
pipes  that  do  not  leak.  In  grading  streets  oftentimes  trees 
are  cut  down  which  could  be  saved  by  a  little  care.  If  the 
street  is  being  cut  down,  the  sidewalk  may  usually  be  run  a 
little  to  one  side  of  the  tree  and  the  dirt  left  as  a  mound  around 
the  tree.  If  the  street  is  being  filled  in,  a  well  of  bricks  may 
be  built  around  the  tree  to  prevent  the  dirt  from  filling  up 
the  space.  When  electric  and  telephone  wires  are  being 
strung,  the  tops  of  trees  are  often  cut  out,  leaving  the  tree 
unsymmetrical  and  disfigured.  Every  city  and  town  should 
have  ordinances  protecting  its  shade  trees  from  these  and 
other  injuries. 

Insect  enemies.  Trees  are  subject  to  injury  from  a  great 
variety  of  insects,  which  may  attack  every  part  of  the  tree. 
One  group  of  insects,  like  the  elm  beetle  and  tussock  moth, 
feed  on  the  leaves,  another  group,  called  borers,  gnaw  their 
way  into  the  bark  and  wood,  destroying  the  cambium  layer ; 
others,  like  the  scales,  suck  the  sap  from  the  leaves  and  other 
soft  parts  of  the  tree.  Some  insects  injure  the  roots  and  some 
the  flower  and  fruit.  These  insects  may  attack  the  trees  in 
such  numbers  that  serious  harm  is  done  in  a  short  time,  or 
the  harm  may  be  extended  over  several  years,  the  trees 
gradually  becoming  weakened,  sometimes  eventually  dying, 
and  in  other  cases  living  for  many  years  in  this  sickly  con- 
dition. Many  of  these  insects  may  be  controlled  by  spray- 
ing. For  biting  insects,  like  the  elm  beetle,  a  poison  such  as 
Paris  green  or  lead  ar senate  is  sprayed  on  the  leaves,  and  the 
insects  are  killed  by  eating  the  poisoned  leaves.  For  suck- 


484  SCIENCE  OF  HOME  AND   COMMUNITY 

ing  insects,  a  poison,  such  as  kerosene  emulsion,  is  sprayed 
directly  on  the  insect,  killing  it  by  contact  or  by  clogging  its 
breathing  tubes.  The  boring  insects  are  very  difficult  to 
control,  but  if  not  present  in  large  numbers,  they  may  be  cut 
out  by  a  knife  or  killed  by  means  of  a  wire.  Sometimes 
insects  may  be  prevented  from  reaching  the  foliage  by  wrap- 
ping bands  of  sticky  material  around  the  trunk  of  the  tree. 

FIELD  EXERCISE  n 

Purpose.  To  learn  what  shade  trees  are  growing  in  your 
town  and  if  they  are  properly  cared  for. 

Directions,  i .  One  purpose  of  the  field  trip  may  be  to  identify 
the  shade  trees  growing  in  the  town.  For  this  purpose  the 
following  points  may  be  observed  regarding  each  tree : 

A.  Character  of  bark  as  to  color  and  roughness. 

B.  Method  of  branching. 

C.  Leaves. 

a.  Kind  —  simple  or  compound. 

b.  Arrangement  —  alternate  or  opposite. 

c.  Margin  —  entire,  toothed,  or  lobed. 

d.  Drawing  of  leaf. 

D.  Flowers. 
£.   Fruit. 

F.    Chief  characters  by  which  identified. 

2.  Observe  the  trees  to  see  if  they  are  being  properly  cared 
for.     Have  the  limbs  been  cut  off  correctly  in  pruning?     Are 
there  any  wounds  that  need  care  to  keep  out  spores  of  disease- 
forming  plants?     Are  there   any  broken  branches  that  need 
pruning?     Are  any  fungi  found  growing  on  the  trees?     Are 
insects  doing  any  serious   damage?     Are  trees  being  injured 
because  horses  are  hitched  to  them  ? 

3.  If  there  is  opportunity  for  planting  trees  around  the  school 
grounds,  the  class  may  plan  to  plant  some  on  Arbor  Day. 


SHADE   TREES   AND    FORESTS  485 

SCHOOL  PROJECT  9 

Purpose.  To  make  an  exhibit  of  leaves  of  trees,  to  which 
you  may  invite  your  friends. 

Directions,  i.  In  connection  with  your  studies  of  trees,  it  will 
be  interesting  for  the  class  to  prepare  a  special  exhibit  of  tree 
leaves  to  which  you  may  invite  your  parents  and  friends.  This 
may  be  made  a  very  pleasant  social  occasion.  The  class  may  be 
divided  into  about  ten  groups,  each  of  which  is  to  collect  leaves 
of  a  certain  family  of  trees,  such  as  the  following :  the  maples, 
the  elms,  the  oaks,  the  birches,  the  willows,  the  poplars,  the 
ashes,  the  nut  trees,  the  locusts,  and  a  miscellaneous  group  to 
include  any  other  trees  not  mentioned.  Each  group  will  try 
to  get  all  the  different  kinds  of  trees  in  his  family  found  growing 
in  the  locality. 

2.  In  order  to  press  the  leaves,  put  them  between  the  folds 
of  newspapers,  place  a  board  on  top  of  the  pile,  and  on  the  board 
put  some  weight,  such  as  books  or  stones.     Allow  them  to  re- 
main for  about  two  weeks.     In  order  to  mount  them,  secure 
some  plain,  white  paper  and  fasten  the  leaves  to  this  by  means 
of  strips  of  gummed  paper.     When  possible,  collect  the  fruit 
as  well  as  the  leaves.     These  mounts  may  be  placed  around  the 
walls  of  the  room. 

3.  If  these  collections  are  made  in  the  late  autumn,  they  may 
be  made  more  attractive  by  securing  colored  leaves. 

4.  In  case  any  questions  may  be  asked  at  the  exhibit  about 
the  tree,  look  up  the  interesting  facts  about  your  trees,  so  that 
you  will  be  ready  to  answer  questions  that  may  be  asked. 

Conservation  of  forests.  When  the  white  man  first  settled 
this  country,  he  found  the  forests  a  barrier  to  his  progress. 
He  was  obliged  to  cut  down  the  trees  in  order  to  raise  the 
crops  that  would  keep  him  and  his  family  from  famine. 
Behind  the  shelter  of  the  trees  lurked  the  Indian,  ready  to 
massacre  his  family  when  a  favorable  opportunity  appeared. 
As  he  looked  westward,  the  long  line  of  unbroken  forest 
impeded  his  march  in  that  direction,  and  we  may  well  under- 
stand that  it  was  with  great  joy  that  the  early  settlers  saw 


486  SCIENCE   OF  HOME   AND    COMMUNITY 

the  forests  give  way  to  fields  of  grain  and  saw  the  boundary 
of  the  unbroken  forest  gradually  recede  westward. 

Conditions  of  forests  to-day.  In  later  years  as  the  market 
value  of  trees  for  their  different  products  attracted  atten- 
tion, the  commercial  spirit  took  control  of  the  forests  and 
there  resulted  a  reckless  devastation  of  forests  carried  on  by 
private  individuals  without  any  effective  effort  on  the  part 
of  the  government  to  stop  or  control  the  waste.  As  a  result 
our  commercial  forests  to-day  are  restricted  to  five  areas: 
northern  New  England;  the  northern  portion  of  Michigan, 
Minnesota,  and  Wisconsin;  the  southern  states;  a  section 
along  the  Rocky  Mountains ;  and  a  section  along  the  Pacific 
Coast  in  Oregon  and  Washington.  A  bulletin  published  by 
the  National  Forest  Service  in  1907  says:  "  This  much  is 
true  beyond  doubt,  that  we  are  dangerously  near  a  hard- 
wood famine  and  have  made  no  provision  against  it." 

This  bulletin  estimates  that  there  were  four  hundred  billion 
feet  of  hardwood  standing  and  that  the  country  was  using 
hardwood  at  the  rate  of  twenty-five  billions  annually.  This 
would  furnish  a  supply  for  only  sixteen  years,  not  consider- 
ing the  amount  of  annual  growth.  This  diminishing  supply 
of  hardwoods  has  been  well  reflected  in  the  advancing  prices. 
Between  1898  and  1907  the  price  of  white  oak  rose  from  $55 
to  $80 ;  of  yellow  poplar  from  $31  to  $53  ;  and  of  hard  maple 
from  $20  to  $32  ;  or  an  increase  of  from  50  to  60  per  cent 
in  ten  years. 

Another  bulletin  published  by  the  Forest  Service  estimates 
that  the  annual  consumption  of  all  kinds  of  wood  in  the 
United  States: is  three  times  the  annual  growth.  At  this  rate 
it  is  estimated  that  the  supply  of  virgin  forests  will  be  ex- 
hausted in  thirty  or  forty  years,  and  then  the  country  must 
depend  on  the  second  growth  of  timber  for  its  supplies.  In 
spite  of  the  substitutes  that  are  being  used  for  wood  in  build- 
ing, the  use  of  wood  is  constantly  increasing,  so  that  more  wood 
per  capita  is  now  being  used  than  ever  before  in  this  country. 


SHADE  TREES  AND   FORESTS  487 

Uses  of  forests.  Forests  serve  three  great  purposes: 
first,  they  act  as  a  protective  covering  on  the  area  on  which 
they  are  growing;  second,  as  a  source  of  wood;  and  third, 
as  a  source  of  beauty  and  pleasure.  The  first  kind  of  forest 
is  called  the  protective  forest ;  the  second,  the  supply  forest ; 
and  the  third,  the  recreation  forest.  The  first  and  third 
uses  are  served  while  the  trees  are  still  standing,  .the  second 
use  after  they  are  cut  down.  By  proper  management,  a 
forest  may  be  made  to  serve  all  three  of  these  purposes. 

The  value  of  forests  as  a  source  of  wood  is  so  evident  that 
it  needs  very  little  explanation.  To  appreciate  this,  one  has 
but  to  think  of  the  manifold  uses  to  which  wood  is  put  every 
day. 

LABORATORY  EXERCISE  37 

Purpose.  To  learn  to  tell  the  cuts  of  wood  found  in  chairs 
and  tables. 

Materials.  Collections  of  small  samples  of  wood,  showing 
different  sections.  Pieces  may  be  obtained  from  a  carpenter's 
shop,  or  small  branches  may  be  collected  from  trees.  Pieces 
from  one  to  two  inches  in  diameter  and  four  inches  long  make 
satisfactory  samples. 

Directions.  A.  Examine  specimens  of  wood  until  you  find 
each  of  the  following : 

1.  Sapwood  and  heartwood.     How  do  these  two  differ? 

2.  Annual  rings  of  growth.     What  differences  do  you  find 

among  the  different  rings  in  the  same  piece  of  wood  ? 
How  old  is  the  piece  ? 

3.  Spring  wood  and  summer  wood  in  the  rings.     How  do 

these  differ? 

4.  The  pores.     Find : 

a.  A  ring-porous  wood,  in  which  the  pores  in  the  spring 

wood  are  larger  and  more  numerous  than  the  pores 
in  the  summer  wood. 

b.  A  diffuse-porous  wood,  in  which  the  pores  are  small 

and  equally  distributed  through  all  the  ring.:,  :;• .-. 

c.  A  non-porous  wood,  in  which  pores  are  absent,  y  ;  b  - 


488  SCIENCE  OF  HOME  AND   COMMUNITY 

5.  Pith  rays. 

6.  Knots. 

B.  The  appearance   of  woods   depends   on   the  way  in  which 

they  are  cut. 

1.  A  cut  made  at  right  angles  to  the  length  is  called  a  trans- 

verse section. 

2.  A  cut  made  lengthwise,  at  about  right  angles  with  the 

rings,  that  is,  nearly  parallel  with  the  pith  rays,  is 
called  radial,  or  quarter-sawed. 

3.  A  cut  made  tangent  to  the  rings,  that  is,  at  right  angles 

with  the  pith  rays,  is  called  tangent  or  bastard. 
Find  three  pieces  of  wood,  one  cut  in  each  of  these  ways,  and 
make  three  labeled  drawings  to  show  whatever  features  men- 
tioned under  A  may  be  present  in  each  section. 

C.  Make  a  drawing  of  a  piece  of  the  desk  about  three  inches 

square,  and  label  the  parts  that  show.  In  which  of  the 
three  ways  was  it  cut?  Look  at  a  number  of  samples 
of  wood  in  chairs,  tables,  etc.,  and  determine  the  cut. 

Forests  as  protective  covers.  As  a  protective  cover,  the 
forest  serves  two  important  purposes :  first,  it  regulates  the 
flow  of  streams ;  and  second,  it  prevents  erosion  of  the  hill- 
sides. On  the  forest  floor  is  a  thick  layer  of  black  humus  r 
composed  of  the  decaying  leaves  and  twigs  which  fall  every 
year  to  the  ground.  This  humus  covers  the  soil  like  a  blanket 
and  exerts  a  very  important  influence  through  its  effect  in 
controlling  the  water  supply  of  streams.  When  rain  falls 
some  evaporates  at  once  and  goes  back  into  the  air ;  some 
runs  off  on  the  surface  and  quickly  gathers  into  streams; 
the  rest  soaks  slowly  down  into  the  soil  and  gradually  comes 
out  again  through  springs  and  streams  and  through  evapo- 
ration from  the  leaves  of  plants.  The  humus  and  mossy 
vegetation  act  as  a  sponge.  They  absorb  a  large  amount  of 
water  and  give  it  out  again  gradually  during  the  dry  spells 
between  rains.  Thus  they  tend  to  prevent  floods  just  after 
a  rain  and  to  prevent  the  drying  up  of  the  streams  during 
the  dry  weather.  Forests  tend,  therefore,  to  give  streams 


'HADE   TRFES   AND   FORESTS 


489 


FIG.  191.  —  Forested  watershed  in  the  San  Bernardino  Mountains,  California. 

a  regular,  even  flow  during  all  the  season,  a  matter  that 
exerts  important  influences  on  our  daily  life,  as  we  shall  see 
in  the  paragraphs  that  follow. 

Streams  for  water  power.  Coal  now  supplies  us  with  most 
of  the  power  to  run  our  factories,  to  furnish  our  electricity, 
and  to  run  our  locomotives  and  other  machines  so  essential 
in  our  life.  But  the  supply  of  coal  will  some  time  be  ex- 
hausted ;  then  man  must  find  some  other  source  of  power. 
Our  streams  will  furnish  a  large  part  of  that  power,  and  the 
force  of  the  flow  may  be  used  over  and  over  at  different 
localities  on  the  stream.  In  order  that  the  best  use  may  be 
made  of  these  streams,  it  is  necessary  that  there  should  be 
an  even  flow  throughout  the  whole  year,  so  that  machines 
may  be  run  all  the  time  and  not  be  obliged  to  stop  because 
the  river  is  low.  It  is  very  important  that  the  people  look 
forward  to  the  time  when  they  must  depend  more  upon 
water  power.  They  should  not  allow  private  capital  to 


490  SCIENCE  OF  HOME  AND   COMMUNITY 

secure  control  and  monopoly  of  this  power.  Immediate 
steps  should  be  taken  by  governments,  both  national  and 
local,  to  secure  supervision  and  control  of  this  great  resource. 
Streams  for  navigation.  As  our  country  continues  to  grow, 
additional  methods  of  transportation  will  be  needed,  and  the 
navigable  rivers  furnish  one  important  means.  Here,  too, 


FIG.  192.  —  Destruction  of  farm  land  by  flood.    North  Carolina. 

it  is  necessary  that  there  should  be  an  even  flow  of  water 
throughout  the  year ;  so  that  the  river  shall  not  be  so  fl6oded 
in  spring  nor  become  so  low  in  summer  that  it  is  not  navi- 
gable. It  is  also  essential  that  the  channel  shall  not  become 
filled  up  with  soil  brought  down  from  the  hills. 

Streams  for  irrigation.  In  the  western  part  of  our  country 
are  vast  areas  with  rich  soil,  capable  of  producing  the  best 
of  crops  and  thus  supporting  a  large  population,  which  never- 
theless are  barren  at  present  on  account  of  lack  of  sufficient- 
rainfall.  In  many  cases  it  is  possible  to  irrigate  the  land  by 


SHADE  TREES  AND   FORESTS 


491 


bringing  water  from  neighboring  rivers.  The  United  States 
government  is  undertaking  large  enterprises  in  this  con- 
nection. It  is  of  special  importance  here  that  as  much  of 
the  water  as  possible  be  available  during  the  dry  seasons'. 
If  no  rains  fall  during  this  season,  it  is  essential  that  the  rain 
which  has  fallen  earlier  in  the  season  shall  be  stored  up  and 
retained  as  long  as  possible  on  the  mountain  slopes  so  as  to 
feed  the  streams  constantly  during  the  dry  season.  In  all 
these  cases  forests  are  essential  to  regulating  the  water  supply 
of  the  streams. 


FIG.  193.  —  Unf crested  watershed  in  the  San  Bernardino  Mountains,  California. 

Prevention  of  soil  erosion.  Another  important  use  of  the 
forest  is  to  prevent  soil  erosion.  The  mulch  prevents  the 
rapid  run-off  which  causes  erosion,  and  the  roots  help  to  keep 
the  soil  in  place.  Where  forests  on  hillsides  have  been  re- 
moved, the  floods  wash  down  the  soil,  carrying  it  into  the 
streams,  thus  interfering  with  navigation  and  sometimes 
spoiling  the  farms  of  the  lowlands  by  deposits  of  gravel 
and  sand.  Sometimes  these  floods  cause  great  injury  to 


492 


SCIENCE  OF  HOME  AND   COMMUNITY 


both  property  and  life.  On  the  steep  hillsides,  the  soil  may 
be  washed  away  down%to  the  solid  rock,  thus  making  it  im- 
possible for  forests  to  grow  there  again. 

In  almost  every  country  there  are  examples  of  this  kind 
where  millions  of  dollars'  worth  of  property  have  been  de- 
stroyed by  floods  owing  to  the  careless  removal  of  forests. 
In  our  own  country,  in  the  state  of  North  Carolina,  land 
which  was  formerly  worth  $125  an  acre  is  now  useless,  owing 


.- .«»v***""*V    '«'.-f^w»    '*  ^•"wSWllp*^1,,xvv)>''' v 

,„.>..-•'  V-  -•^V'^^^C^^^^^if'^^'  .r-"'1"   t"""^- 
FIG.  194.  —  A  park,  a  place  where  people  may  enjoy  the  outdoors. 

to  gullies  and  deposits  of  gravel  due  to  floods.  In  the  San 
Bernardino  Mountains  in  California,  torrents  have  been 
able  to  carry  stones  and  sand  into  the  orange  groves  of  the 
San  Gabriel  valley,  because  of  the  destruction  of  forests  on 
the  mountains  by  fires  and  grazing. 

Recreation  forests.  The  recreation  forest  serves  an  im- 
portant purpose  as  a  source  of  pleasure.  Many  travelers 
and  campers  visit  the  national  parks  and  forests  each  sum- 
mer as  a  means  of  recreation,  and  the  smaller  parks  found  in 
cities  and  towns  are  of  great  value  to  the  people  living  near. 


SHADE  TREES  AND   FORESTS  493 

It  is  estimated  that  during  the  summer  of  1917,  3,000,000 
persons  entered  the  national  forests  for  some  kind  of  recre- 
ation. The  chief  kinds  of  recreation  are  fishing,  camping, 
hiking,  packing,  automobiling,  and  picnicking.  Hundreds 
of  miles  of  trails  have  been  built  for  hikers  and  pack  ani- 
mals, and  many  miles  of  roadway  for  automobiles  and 
wagons.  To  meet  the  needs  of  the  tourists,  the  Forest 
Service  has  laid  out  and  equipped  a  large  number  of  camps 
along  these  trails. 

COMMUNITY  PROJECT  7 

Purpose.     To  learn  the  value  of  your  city  parks. 

Directions,  i.  Visit  a  park  and  make  a  list  of  the  trees, 
shrubs,  vines,  and  flowers  growing  there. 

2.  Find  information  regarding  your  city  parks,  on  the  follow- 
ing points :  number  and  area,  money  spent  each  year  on  them, 
care  given  to  them,  improvements  made,  uses  made  of  the  parks, 
number  of  people  using  them. 

National  forests.  Realizing  the  importance  of  conserving 
our  forests,  the  national  government  began,  during  the  ad- 
ministration of  President  Harrison,  to  set  aside  from  the 
lands  which  it  owned  certain  areas  to  be  kept  as  national 
forests.  Since  that  time,  others  have  been  added,  till  to- 
day there  are  151  national  forests,  comprising  an  area  of 
156,000,000  acres,  or  about  one  fifth  of  the  forests  in  the 
United  States.  These  are  located  chiefly  in  the  western 
states,  although  national  forests  have  recently  been  set  aside 
in  the  White  Mountains  and  in  the  Appalachian  Mountains. 
These  forests  generally  constitute  lands  which  are  not 
adapted  for  purposes  of  agriculture  and  can  serve  their  best 
purpose  by  being  allowed  to  remain  in  forests. 

It  is  the  intention  of  the  government  to  make  the  forests 
of  the  greatest  use  to  all  concerned.  The  forests  are  managed 
in  such  a  way  as  to  insure  their  permanency  and  only  the 


494  SCIENCE  OF  HOME  AND   COMMUNITY 

fully  matured  trees  are  cut,  the  smaller  trees  being  allowed 
to  grow  till  ready  to  be  cut.  When  sections  of  the  forest 
lands  are  found  which  are  adapted  to  agriculture  these 
are  given  out  as  homesteads.  In  some  forests  cattle  and 
sheep  are  allowed  to  graze.  Campers  and  other  pleasure 
seekers  are  encouraged  to  use  the  forests.  Furthermore, 
opportunity  is  given  here  for  game  to  increase.  So  that 
the  purpose  is  not  to  withdraw  the  forests  from  use,  as 
is  sometimes  erroneously  thought,  but  to  make  them  as 
useful  as  possible  and  to  place  them  under  scientific  manage- 
ment. 

The  following  figures  suggest  the  extent  to  which  they  are 
being  used.  These  forests  are  supplying  annually  fuel  and 
fencing  to  the  value  of  $196,000  to  38,000  people  living  near. 
The  receipts  from  the  forests  for  the  year  ending  June  30, 
1917,  were  $3,450,000.  The  forests  furnish  opportunity  for 
grazing  to  1,500,000  cattle  and  horses  and  to  more  than 
14,000,000  sheep.  1175  towns  and  cities  and  324  irrigation 
and  power  projects  took  their  water  from  streams  that  had 
their  headwaters  in  the  national  forests. 

In  the  care  of  these  national  forests,  scientific  forestry  is 
practiced.  This  consists  essentially  in  three  things :  first, 
in  cutting  only  the  large,  mature  trees,  leaving  the  others  to 
grow ;  second,  in  providing  seedlings  and  young  trees  to 
take  the  place  of  those  being  cut ;  and  third,  in  protecting 
the  forests  from  fires  and  other  enemies. 

The  big  trees.  There  has  recently  been  set  aside  as  a 
national  park,  an  area  in  California  that  contains  the  famous 
big  trees.  These  are  the  most  marvelous  trees  in  this 
country  and  perhaps  in  the  world. 

Some  of  the  largest  of  these  have  received  special  names, 
such  as  General  {pherman  and  General  Grant.  General 
Sherman,  the  largest  of  all,  is  279.9  feet  high  and  36.5  feet 
in  diameter.  It  is  believed  to  be  about  3500  years  old.  It 
was  a  seedling  in  the  days  of  Moses.  When  Jesus  was  born, 


SHADE   TREES   AND   FORESTS  495 

it  was  a  youth  of  1500  summers.  Thousands  of  the  trees 
now  standing  in  the  Sequoia  National  Park  were  growing 
during  the  time  of  Caesar.  Hundreds  were  flourishing  while 
Babylon  was  in  its  prime.  Several  are  older  than  the  Pyra- 
mids of  Egypt.  Four  thousand  rings  were  counted  on  one 
prostrate  tree.  This  tree  probably  sprouted  while  the  tower 
of  Babel  was  still  standing.  It  was  a  large  tree,  two  thou- 
sand years  old,  when  David  was  born.  It  is  believed  by  the 
best  authorities  that  some  of  the  trees  now  standing  are  five 
thousand  years  old.  It  is  difficult  to  conceive  that  a  single 
individual  has  lived  that  long. 

State  forests.  The  state  governments  are  also  beginning 
to  set  aside  forests.  Thirty  states  have  a  forestry  depart- 
ment and  twenty  have  trained  foresters  in  charge  of  their 
work.  These  states  have  one  hundred  and  forty-two  forests 
with  an  area  of  three  and  a  half  million  acres.  New  York 
State  leads  with  i  ,600,000  acres ;  then  comes  Pennsylvania 
with  nearly  a  million;  Wisconsin  with  400,000;  Michigan 
with  231 ,000  and  other  states  with  smaller  forests.  Fourteen 
states  have  set  aside  forests. 

Some  towns  are  beginning  to  set  aside  municipal  forests. 
There  are  at  the  present  time  ninety-seven  municipal 
forests  situated  in  thirteen  states.  More  than  half  of  these, 
fifty-six,  are  situated  in  Massachusetts. 

United  States  Forest  Service.  In  connection  with  the 
development  of  the  system  of  national  forests,  there  has 
grown  up  as  a  part  of  the  government,  the  United  States 
Forest  Service,  a  part  of  the  Department  of  Agriculture, 
whose  chief  duty  is  to  look  after  the  protection  and  use  of 
the  national  forests.  Some  of  the  work  of  the  service  is 
done  in  Washington  and  some  in  the  national  forests. 

The  direct  care  of  the  forest  is  intrusted  to  the  ranger. 
His  most  important  duty  is  to  protect  the  district  in  his 
charge  against  fires.  During  certain  seasons  he  patrols  his 
district  by  means  of  trails  and  bridges  for  the  purpose 


496  SCIENCE  OF  HOME  AND   COMMUNITY 

of  watching  for  fires.  Another  important  duty  of  the 
ranger  is  to  look  after  the  sale  of  timber  and  to  mark  the 
trees  that  are  to  be  cut.  The  ranger  also  supervises  the  use 
of  the  forest  for  the  grazing  of  cattle  and  sheep.  The  guards 
are  the  assistants  of  the  rangers  and  may  be  called  upon  to 
do  the  same  kind  of  work. 

The  Forest  Service  has  been  an  efficient  agent  in  awaken- 
ing the  people  of  the  country  to  the  need  of  conserving  our 
forests.  Since  1900,  it  has  issued  three  hundred  and  seventy 
publications  with  a  total  circulation  of  almost  twelve  million 
copies.  All  together  the  Forest  Service  now  numbers  more 
than  three  thousand  members. 

Enemies  of  the  forest.  Fires.  Fires  are  the  most  de- 
structive enemy  of  the  forests,  the  annual  amount  of  damage 
being  about  fifty  million  dollars.  Each  year  twenty  million 
acres  of  forest  land,  an  area  nearly  four  times  the  size  of 
Massachusetts,  is  burned  over.  It  is  estimated  that  the 
amount  of  timber  destroyed  by  fire  is  equal  to  that  cut  and 
used.  Some  fires  have  become  historic  on  account  of  the 
amount  of  damage -done.  The  Hinckley  fire  in  Minnesota 
in  1894  destroyed  nine  towns,  burned  twenty-five  million 
dollars'  worth  of  property,  and  killed  six  hundred  people. 

The  chief  harm  done  by  fires  is  in  the  destruction  of  stand- 
ing timber.  Indirectly,  harm  is  also  done  to  those  trees 
which  are  only  partly  destroyed  by  fire,  for  they  are  easily 
blown  over  by  winds  or  fall  easy  victims  to  the  attacks  of 
insects  and  wood-destroying  fungi.  Another  great  injury 
is  the  destruction  of  seedlings  and  young  trees  on  which 
the  future  of  the  forests  depends.  Sometimes  enough  of 
the  humus  is  burned  so  as  to  interfere  with  the  work  of  the 
forest  in  controlling  the  run-off  and  preventing  floods. 

Kinds  of  fires.  Fires  are  frequently  classified  into  sur- 
face, crown,  and  ground  fires  according  to  the  manner  in 
which  they  burn.  Surface  fires  run  along  the  ground, 
consuming  only  the  leaves  and  twigs  found  there.  The 


SHADE  TREES  AND  FORESTS 


4^7 


tie.  195.  —  Fallen  and  standing  fire-killed  timber,  Priest  River  Reserve,  Idaho. 

crown  fires  run  up  into  the  crowns  of  the  trees  and  burn  the 
leaves  and  small  branches.  These  occur  only  in  the  ever- 
green forests.  Ground  fires  burn  in  the  duff  below  the  sur- 
face, and  may  burn  for  weeks  and  even  months  without 
ax 


498  SCIENCE  OF  HOME  AND   COMMUNITY 

showing  any  signs  of  life  and  then  may  break  out  in  an  un- 
expected place  even  after  a  heavy  rain. 

Causes  of  fires.  The  most  common  cause  of  forest  fires 
is  the  railroad  locomotive  which  sends  out  sparks  that 
readily  ignite  the  dry  leaves  and  grass  along  the  railroad. 
Other  forest  fires  are  caused  by  burning  brush,  by  lightning, 
by  fires  which  are  started  purposely  to  improve  grazing  or 
for  other  purposes,  and  by  careless  campers  who  fail  to  com- 
pletely extinguish  a  camp  fire  when  leaving  it. 

Prevention  and  control  of  fires.  Most  fires  are  due  to  care- 
lessness and  can  be  prevented  if  proper  precautions  are 
taken.  In  lumbering,  proper  disposal  should  be  made  of 
the  small  branches  either  by  piling  and  burning  them  or  by 
lopping  and  scattering  the  brush,  which  soon  rots.  Spark 
arresters  may  be  placed  on  locomotives  to  prevent  the  sparks 
from  being  thrown  out,  or  oil  or  electricity  may  be  used  in 
place  of  coal.  Fire  lanes  from  which  inflammable  material 
has  been  cleared  may  be  constructed  to  prevent  the  spread 
of  fires.  In  the  national  forests  trails  are  made  so  that  the 
rangers  may  patrol  the  forests ;  lookout  points  and  observa- 
tion towers  are  constructed,  connected  by  telephone  with  the 
nearest  town. 

Putting  out  fires.  Small  fires  may  be. controlled  by  throw- 
ing dirt  on  them.  In  fighting  ground  fires,  a  trench  must 
be  dug  through  the  forest  floor  down  to  the  soil.  Severe 
fires  may  be  controlled  by  back-firing.  A  second  fire  is 
started  some  distance  ahead  and  allowed  to  burn  against 
the  wind  to  meet  the  chief  fire.  Great  care  must  be  taken 
that  the  back-fire  itself  does  not  spread.  This  is  prevented 
by  starting  it  to  the  windward  of  a  road  or  fire  line,  or  other 
barrier  which  the' fire  can  be  kept  from  crossing. 

Destructive  lumbering.  One  of  the  chief  causes  for  the 
decrease  of  our  forests  has  been  the  wasteful  method  of  lum- 
bering. The  general  policy  followed  has  been  to  cut  down 
all  the  growth  at  one  time,  securing  just  one  crop  and  making 


SHADE  TREES  AND  FORESTS 


499 


no  plans  for  future  returns.  Usually  the  piles  of  brush  left 
have  been  a  prolific  means  for  the  spread  of  forest  fires. 
Sometimes  this  short-sighted  policy  has  been  hastened  by 
the  fear  of  possible  loss  through  fires  and  by  high  taxes  which 
rendered  it  unprofitable  to  hold  the  land  for  more  than  one 
crop. 

Grazing.     Grazing  may  do  injury  to  the  forests  if  not 
properly  regulated.     The  sheep  trample  the  young  growth 


FIG.  196.  —  Destructive  lumbering.    The  slash  enabled  fire  to  complete  the  ruin. 

under  foot  and  destroy  small  trees  by  browsing  on  the  young 
shoots.  Sheep  may  also  pulverize  the  forest  floor,  allowing 
it  to  be  washed  away  by  storms.  This  matter  is  being 
carefully  regulated  in  the  national  forests,  and  less  harm  is 
done  than  formerly. 

Insects.  It  has  been  estimated  that  insects  cause  an 
annual  loss  to  trees  in  this  country  of  one  hundred  million 
dollars.  There  are  hundreds  of  species  of  insects  found 
attacking  the  forest  trees,  but  the  greater  amount  of  the 
damage  is  done  by  a  comparatively  small  number  of  species. 


500  SCIENCE  OF  HOME  AND   COMMUNITY 

Some  attack  the  living  tree,  some  attack  only  the  dead  and 
dying  trees,  and  others  do  harm  to  sawed  lumber  and  wood 
products. 

Conservation  of  forests.  Conservation  of  forests  simply 
means  that  the  forests  should  be  cared  for  in  a  scientific 
manner.  By  proper  methods  of  forestry,  it  is  possible  to 
cut  some  of  the  trees  and  still  leave  enough  for  protective 
cover.  In  cutting  trees  it  is  not  well  to  cut  all  in  a  certain 


FIG.  197.  —  Larch  trees  killed  by  the  larva  of  a  small  sowfly.     Adirondack 
Mountains,  New  York. 

area,  but  only  a  few  of  the  largest  should  be  cut  each  year, 
leaving  the  rest  to  serve  their  protective  purpose.  By 
leaving  spaces  where  seeds  may  fall  and  germinate  and 
seedlings  grow,  a  supply  of  young  trees  is  kept  constantly 
growing  to  take  the  place  of  those  which  are  being  cut  out. 
In  this  way  a  forest  may  be  so  managed  as  to  give  a  constant 
supply  of  timber  for  centuries,  unless  it  is  overtaken  by  some 
calamity  such  as  a  fire  or  a  ravage  of  insects.  Through 
proper  care  the  forests  still  left  may  continue  to  furnish 


SHADE  TREES   AND   FORESTS  531 

almost  indefinitely  the  supply  of  timber  needed.  The  great 
difficulty  in  the  past  has  been  the  wasteful  and  unscientific 
methods  used  and  the  disregard  for  the  future.  Switzer- 
land's forests  have  been  properly  cared  for  during  the  past 
centuries  so  that  they  are  more  efficient  and  valuable  now 
than  they  were  hundreds  of  years  ago.  We  may  attain  the 
same  condition  in  this  country  if  the  government  will  acquire 
a  larger  number  of  national  forests  and  will  regulate  the 


FIG.  198.  —  Conservative   lumbering.     Young   growth   saved,    brush   piled   to 

prevent  fire. 


cutting  in  private  forests  as  well.  This  is  a  matter  of  such 
concern  to  the  general  good  as  to  require  government  super- 
vision. The  cutting  of  the  forests  does  not  concern  merely 
the  men  owning  the  forests,  but  it  concerns  the  welfare  of 
the  entire  communities  living  near  the  streams  which  rise 
in  the  sections  where  these  forests  are  situated.  The  gov- 
ernment should  make  and  enforce  regulations  which  will 
stop  the  owners  of  these  forests  from  treating  their  forests 
in  such  a  way  as  to  injure  other  people. 


502  SCIENCE   OF   HOME   AND    COMMUNITY 

SUPPLEMENTARY  QUESTIONS  FOR  CLASS  DISCUSSION 

1 .  Which  do  you  consider  the  most  valuable  type  of  forest : 
the  protective,  the  supply,  or  the  recreative  ?     Why  ? 

2.  Why  is  it  important  that  the  flow  of  streams  should  be  kept 
constant  ? 

3.  What  harm  results  from  removing  forests? 

4.  What  constitutes  proper  care  of  forests? 

5.  How  may  the  forests  be  protected  from  their  enemies? 


REFERENCES 

Going,  Our  Field  and  Forest  Trees,  A.  C.  McClurg  Co.,  Chicago. 
Levison,  Studies  of  Trees,  J.  Wiley  and  Sons,  New  York  City. 
Peet,  Practical  Tree  Repair,  McBride  Nast  and  Co.,  New  York 

City. 
Roth,  A  First  Book  of  Forestry,  Ginn  and  Co.,  Boston. 


SECTION   F 
PROTECTION  FROM  WEATHER 

CHAPTER  XXXI 

THE   UNITED   STATES  WEATHER   BUREAU 
How  is  it  possible  to  foretell  the  weather  ? 

Use  of  weather  forecasts.  Value  to  fruit  growers.  In 
the  springtime  there  is  danger  that  the  blossoms  of  fruit 
trees  may  be  destroyed  by  late  frosts.  In  some  orchards 
arrangements  are  made  for  lighting  fires  quickly  in  order  to 
save  the  orchards.  When  there  is  danger  that  a  frost  may 
occur,  the  United  States  Weather  Bureau  sends  notice  to 
the  fruit  growers.  They  then  build  fires  and  are  thus  able 
to  save  their  crops  by  receiving  this  warning.  Sometimes 
the  value  of  the  fruit  thus  saved  in  a  single  night  in  one 
state  has  been  as  high  as  $100,000;  and  during  a  year 
throughout  the  whole  country  it  has  been  as  much  as  $3,000,- 
ooo.  As  we  learned  in  Chapter  XXII,  a  three-million-dollar 
fruit  crop  was  saved  in  Colorado  through  a  warning  of 
approaching  frost  sent  the  fruit  growers  by  the  United 
States  Weather  Bureau.  In  the  state  of  California  alone, 
fruit  valued  at  $14,000,000  has  been  saved  in  a  single  year 
by  warnings  of  cold  waves  issued  by  the  Weather  Bureau. 

Protection  of  ships.  Warnings  of  severe  storms  are  sent 
to  the  leading  ports  on  the  oceans  and  Great  Lakes.  Ship 
owners  are  thus  able  to  regulate  the  times  of  sailing  of  the 

503 


504  SCIENCE  OF  HOME  AND   COMMUNITY 

boats ;  and  in  this  way  many  dollars'  worth  of  property 
and  many  lives  are  saved.  A  single  storm  warning  has 
been  known  to  keep  in  port  vessels  and  cargoes  valued  at 
$30,000,000. 

Protection  from  floods.  When  floods  are  threatening  on 
account  of  heavy  rains,  warnings  are  sent  to  the  people 
living  along  the  banks  of  rivers.  In  1912  the  Weather 
Bureau  sent  warnings  to  the  people  living  along  the  Missis- 
sippi River  that  there  was  to  be  a  severe  flood.  As  a  result, 
the  people  living  near  the  river  were  able  to  remove  their  cattle 
and  other  property  and  the  freight  at  the  wharves  to  a  place 
of  safety.  It  was  estimated  that  property  to  the  value  of 
$61,000,000  was  thus  saved. 

It  is  estimated  that  the  total  value  of  the  property  saved 
each  year  through  the  warnings  issued  by  the  Weather 
Bureau  is  $30,000,000. 

Besides  the  saving  of  lives  and  property  thus  effected, 
the  weather  forecasts  made  by  the  Bureau  and  printed  in 
the  daily  papers  are  of  some  value  to  people  in  making  their 
plans. 

How  is  the  Weather  Bureau  able  to  make  these  forecasts 
of  weather  so  as  to  foretell  frosts,  storms,  floods,  and  gen- 
eral weather  conditions?  This  is  done  by  means  of  the 
weather  map.  In  order  to  understand  the  method  of  using 
it,  we  will  look  at  the  map  shown  in  figure  199. 

Description  of  weather  map.  Two  sets  of  lines  arranged 
in  irregular  curves  are  found  on  the  map,  the  solid  lines  and 
the  broken  lines.  The  solid  lines  show  the  air  pressure  and 
are  called  isobars.  They  are  marked  in  tenths  of  an  inch. 
The  line  marked  30.2  means  that  all  the  places  through  which 
this  passes  have  a  pressure  of  30.2  inches.  These  are  made 
for  every  tenth  of  an  inch.  Two  kinds  of  areas  are  found  on 
the  map,  "  high  "  and  "  low."  This  refers  to  the  air  pres- 
sure. In  general  a  low  area,  called  a  cyclone,  is  accompanied 
by  clouds,  precipitation,  and  warmer  temperatures.  The 


THE   UNITED   STATES   WEATHER   BUREAU 


506  SCIENCE  OF  HOME  AND   COMMUNITY 

high  areas  are  usually  accompanied  by  clear  weather  and 
lower  temperatures. 

The  broken  lines  are  called  isotherms  and  show  places  of 
equal  temperatures.  The  line  marked  40  degrees  passes 
through  all  places  with  40  degrees  temperature.  These  are 
made  for  every  10  degrees.  Arrows  are  used  to  indicate 
the  direction  of  the  wind.  These  fly  with  the  wind,  just 
opposite  to  the  way  a  weather  vane  points.  For  example, 
an  arrow  pointing  like  this  — >-  means  that  the  wind  is 
blowing  towards  the  east,  and  we  call  this  a  west  wind  be- 
cause it  blows  from  the  west.  The  circles  at  the  ends  of 
the  arrows  indicate  the  state  of  weather.  Their  meanings 
are  given  in  the  explanation  accompanying  figure  199. 

On  the  complete  maps  shaded  areas  show  precipitation  of 
.01  inch  or  more  during  the  last  24  hours.  A  table  at  the 
lower  right-hand  corner  gives  the  maximum  and  minimum 
temperatures,  the  wind  velocity  in  miles  per  hour,  and  the 
precipitation  in  inches  during  the  last  24  hours.  In  the 
lower  left-hand  corner  are  given  the  forecasts  for  the  next  day. 

How  figures  are  obtained.  These  facts  regarding  the 
weather  are  obtained  daily  from  observers  situated  in  about 
200  stations  in  various  parts  of  the  United  States  and  Canada. 
Each  morning  at  eight  o'clock  these  observers  telegraph 
to  Washington  and  to  other  leading  cities  the  temperature, 
the  air  pressure,  the  precipitation,  the  direction  and  velocity 
of  the  wind,  and  the  condition  of  the  sky,  whether  clear  or 
cloudy. 

Weather  instruments.  In  order  to  measure  these  con- 
ditions accurately  instruments  are  used,  the  chief  ones  being 
the  barometer,  the  thermometer,  and  the  rain  gauge. 

Air  pressure.  The  pressure  of  the  air  is  measured  by  the 
barometer.  The  air  that  surrounds  us  has  weight  (as  we 
have  already  seen  in  Chapter  IV),  although  we  do  not  or- 
dinarily feel  it.  But  when  a  strong  wind  is  blowing,  we  get 
some  idea  of  the  reality  of  this  weight.  Some  simple  ex- 


THE  UNITED   STATES   WEATHER  BUREAU  507 


508  SCIENCE  OF  HOME  AND   COMMUNITY 

periments  were  performed  in  a  previous  chapter  to  show  that 
air  has  weight.  This  fact  has  not  been  known  for  very  many 
years. 

Torricelli's  experiment.  Nearly  three  hundred  years  ago, 
a  man  named  Torricelli  first  performed  an  experiment  which 
showed  that  air  exerts  pressure.  This  experiment  has  be- 
come historic  and  has  been  performed  many  times  since. 
We  will  perform  it  now  because  it  will  help  us  better  to 
understand  the  principle  of  the  barom- 
eter by  which  air  pressure  is  measured. 
We  shall  need  a  dish  of  mercury  and 
a  glass  tube  about  three  feet  long, 
closed  at  one  end.  The  tube  is  filled 
with  quicksilver,  the  thumb  placed  over 
the  end,  and  the  tube  inverted  in  the 
dish  of  mercury.  The  thumb  is  re- 
moved after  the  open  end  is  under  the 
surface  of  the  mercury.  The  mercury 
in  the  tube  falls  about  six  inches  and 
then  stops.  It  is  held  up  by  the  pres- 
sure of  air  exerted  on  the  surface  of  the 

FIG.  2oi.-Torricelli's    mercury. 

experiment.  The  barometer.     This  shows  the  prin- 

ciple used  in  the  construction  of  barometers.  The  height 
of  mercury  is  a  standard  by  which  to  measure  the  pressure 
of  air.  The  weight  of  this  column  of  mercury  is  just  equal 
to  the  weight  of  a  column  of  air  of  the  same  diameter  and 
extending  up  as  far  as  the  air  goes,  which  is  fifty  miles  or 
so.  So  that  a  column  of  air  fifty  miles  high  is  equal  to 
the  weight  of  a  column  of  mercury  about  thirty  inches  high. 
Figure  202  shows  an  ordinary  mercurial  barometer.  It  is 
built  on  the  principle  of  the  apparatus  used  in  Torricelli 's 
experiment.  The  tube  above  the  mercury  contains  a  vacuum; 
there  is  no  air  there  to  prevent  the  mercury  from  moving  up 
the  tube. 


THE   UNITED    STATES   WEATHER   BUREAU 


509 


The  pressure  of  the  air  is  constantly  changing.  When 
the  pressure  becomes  greater,,  the  mercury  in  the  tube  rises ; 
and  when  the  pressure  becomes  less  the  mer- 
cury falls.  Thus  a  change  in  the  height  of  the 
mercury  shows  a  change  in  the  pressure  of  the 
air.  This  pressure  is  measured  in  terms  of  the 
height  of  the  mercury  column  in  inches.  Thirty 
inches  is  the  average  pressure  at  sea  level. 
This  means  that  the  air  exerts  a  pressure  of 
about  fifteen  pounds  on  every  square  inch  on 
which  it  rests,  or  a  pressure  of  about  a  ton  on 
every  square  foot.  The  reason  that  buildings 
and  other  objects  are  not  crushed  by  this 
weight  is  because  the  air  pressure  beneath  and 
within  hollow  objects  is  equal  to  the  pressure 
bearing  down,  and  so  the  two  balance. 

Use  for  measuring  heights.  As  one  goes  up 
a  mountain  or  in  a  balloon,  the  amount^  of  air 
above  one  becomes  less  and  so  bears  down  on 
the  mercury  of  a  barometer  less  heavily ;  there- 
fore the  column  of  mer- 
cury falls.  Because  of 
this,  the  barometer  can 
be  used  to  determine 
heights  of  mountains 
and  other  elevations. 
The  higher  one  goes, 
the  lower  the  mercury  FIG.  202.  —  A 
drops.  For  the  first 
mile  the  mercury  drops 
one  inch  for  every  nine  hundred 
or  thousand  feet.  At  a  height  of 
two  miles  the  mercury  drops  to  twenty  inches. 

Aneroid  barometer.     As  the  mercurial  barometer  is  awk- 
ward to  carry,  another  form  called  the  aneroid  barometer 


standard  ba- 
rometer. 


FIG.  203.  —  Aneroid  barometer. 


SCIENCE  OF  HOME  AND   COMMUNITY 


is  used  to  determine  elevation;  as  shown  in  figure  203,  this 
looks  something  like  a  clock.  The  back  is  covered  with  a 
very  thin  diaphragm  which  is  pressed  down  by  the  weight 
of  the  air.  This  is  connected  with  a  hand  on  the  front  which 
records  the  pressure. 

DEMONSTRATION  35 

Purpose.    To  find  the  height  of  a  hill  by  means  of  a  barometer. 

Directions.  Take  the  reading  of  the  barometer  at  the  top  of 
the  hill.  Take  it  again  at  the  bottom.  Subtract  these  readings. 
The  approximate  height  may  be  found  by  multiplying  by  ninety 
this  difference  expressed  in  tenths  of  an  inch. 

Barometer  and  weather  predictions.  The  barometer  is  a 
very  important  instrument  in  making  weather  observa- 
tions, because  the  air  pressure  is  the  most  important  factor 
in  foretelling  weather  changes.  In  general  a  rising  barom- 
eter indicates  fair  weather,  while  a  falling  barometer  indi- 
cates stormy  weather. 

Thermometers.  For  measuring  the  prevailing  tempera- 
ture, the  thermometer  is  used,  as  explained  in  Chapter  I. 


FIG.  204.  —  Minimum  and  maximum  thermometers. 

Besides  this,  maximum  and  minimum  thermometers  are 
used  to  record  the  highest  and  the  lowest  temperatures. 
These  thermometers  will  register  the  highest  and  the  lowest 
temperatures  for  the  time  they  are  left.  They  are  usually 
set  every  day.  The  maximum  thermometer  is  constructed 
so  that  some  of  the  mercury  remains  at  the  highest  point 
to  which  it  is  forced.  The  minimum  thermometer  is  so 
constructed  that  a  small  index  moves  with  the  liquid  and 


THE   UNITED    STATES   WEATHER   BUREAU 


remains  at  the  lowest  point  reached.     Each  of  these  can 
then  be  set  again. 

Rain  gauge.  In  order  to  measure  the  amount  of  rain, 
a  rain  gauge  is  used  (figure  205).  This  is  so  constructed 
that  the  area  of  the  top  of  the  funnel,  which  receives  the 
rain,  is  ten  times  the  area  of  the  small  tube  in  which  it  col- 
lects. This  raises  the  level  of  the  water  ten  times  as.  high, 
and  makes  it  easier  to  read.  This  is  measured  by  means  of 
a  ruler  and  the  result  is 
divided  by  ten  to  get  the 
true  rainfall.  In  order 
to  measure  snow,  a  vol- 
ume equal  in  area  to  the 
top  of  the  funnel  and  as 
deep  as  the  fall  of  snow 
is  collected  and  melted, 


Front  Vtew         Vertical  Section. 


Receiver. 


FIG.  205.  —  Rain  gauge. 


and  the  water  is  meas- 
ured the  same  as  the  rain. 

When  the  reports  of 
the  weather  made  by  the 
observers  in  various 
parts  of  the  country 
have  been  received  at  Washington  and  other  cities,  the  fig- 
ures are  put  down  in  their  proper  places  on  a  blank  map 
of  the  United  States ;  from  these  a  weather  map  like  that 
shown  in  figure  199  is  constructed. 

Weather  forecasts.  This  map  when  completed  gives  a 
general  view  of  the  weather  conditions  for  the  day  through- 
out the  whole  country.  Having  made  this  map,  how  are 
the  weather  forecasters  able  to  foretell  what  the  weather 
for  a  certain  place  will  be  on  the  following  day?  A  study 
of  a  great  many  maps  for  many  years  has  shown  that  after 
a  low  area  has  formed  in  the  western  part  of  the  country, 
it  moves  across  the  country  in  an  easterly  direction  at  the 
rate  of  several  hundred  miles  a  day.  This  speed  varies 


512  SCIENCE  OF  HOME  AND   COMMUNITY 

according  to  season,  being  about  eight  hundred  miles  a  day 
in  winter  and  about  five  hundred  miles  in  summer.  In  a 
similar  way,  the  high  areas  move  in  an  easterly  direction. 
The  weather  experts  are  able  to  prophesy  about  how  far 
the  areas  will  travel  by  the  next  day,  and  hence  what  weather 
conditions  will  be  brought  to  the  various  localities. 

To  put  it  in  another  way,  if  one  wishes  to  ascertain  the 
weather  conditions  that  he  will  find  in  his  locality  at  the  end 
of  twenty-four  hours,  he  can  look  at  the  weather  conditions 
found  in  the  area  situated  several  hundred  miles  west  of 
him,  as  far  west  as  a  low  area  travels  in  one  day. 

These  maps  are  made  not  only  at  Washington  but  in  many 
other  large  cities  and,  with  the  forecast  printed  on  them,  are 
sent  into  the  surrounding  sections  of  the  country.  A  brief 
forecast  is  given  to  the  daily  newspapers. 

These  forecasts  are  right  in  about  ninety  per  cent  of  the 
predictions  and  constitute  the  only  reliable  method  of  fore- 
telling weather.  Sometimes  forecasts  are  made  for  two 
days  ahead ;  but  the  longer  ahead  the  forecast  is  made, 
the  more  unreliable  it  is,  because  the  low  areas  undergo 
so  many  changes  as  they  pass  across  the  country  that  it  is 
possible  to  foretell  for  only  a  short  time  what  the  weather 
changes  will  be. 

LABORATORY  EXERCISE  38 

Purpose.  To  keep  a  record  of  weather  conditions  by  means  of 
instruments. 

Materials.  Barometer,  ordinary  thermometer,  maximum  and 
minimum  thermometer,  weather  vane. 

Directions.  I.  Copy  the  table  given  on  page  513  in  your  note- 
book. Between  eight  and  nine  each  morning  make  the  observa- 
tions called  for  and  put  the  record  in  your  notebook. 

The  record  of  the  force  of  the  wind  may  be  kept  in  accordance 
with  the  following  scale  proposed  by  the  U.  S.  Weather  Bureau : 
o,  calm ;  I ,  light,  just  moving  the  leaves  of  trees ;  2,  moderate, 
moving  branches;  3,  brisk,  swaying  branches,  blowing  up  dust; 


THE  UNITED   STATES  WEATHER  BUREAU 


513 


4,  high,  swaying  whole  trees,  blowing  up  twigs  from  the  ground ; 

5,  gale,  breaking  small  branches,  blowing  loose  bricks  from  chim- 
neys ;  6,  hurricane  or  tornado,  destroying  everything  in  its  path. 


DATE 

HOUR 

PRES- 
SURE 

TEMPERATURE 

CLOUDS 
(amount 
in 
tenths) 

PRECIP- 
ITATION 

WINDS 

Current 

Maxi- 
mum 

Mini- 
mum 

Direc- 
tion 

Force 

2.  It  may  be  well  to  have  the  class  divided  into  sections  and 
allow  each  section  to  keep  the  records  for  a  certain  time,  so  that 
all  together  may  keep  the  record  for  a  large  part  of  the  school  year. 

3.  After  the  records  have  been  kept  for  a  month  or  longer  study 
them  to  see  if  you  find  any  relation  between  (a)  pressure  and  tem- 
perature, (&)  pressure  and  precipitation,  (c~)  pressure  and  direction 
of  wind,  (d)  pressure  and  cloudiness,  (e)  precipitation  and  direction 
of  winds,  (/)  temperature  and  direction  of  winds. 

LABORATORY  EXERCISE  39 

Purpose.  To  learn  how  one  may  foretell  the  weather  by  a 
study  of  weather  maps. 

Materials.     Series  of  consecutive  weather  maps. 

Directions,  i.  Find  each  of  the  following  on  the  map  and 
explain  what  it  signifies :  (a)  the  continuous  black  lines ;  (b)  the 

2L 


5H  SCIENCE  OF  HOME  AND   COMMUNITY 

dotted  black  lines ;  (c)  the  circles ;  (d)  the  arrows  attached  to 
the  circles;  (e)  the  shaded  areas;  (f)  the  words  "  high  "  and 
"  low." 

2.  On  the  map  find  the  place  that  had  (a)  the  highest  tem- 
perature, (b)  the  lowest  temperature,  (c)  the  greatest  air  pressure, 
(d)  the  least  air  pressure.     In  the  columns  find  the  place  that 
had    (a)    the   highest   maximum   temperature,    (b)    the   lowest 
minimum  temperature,   (c)  the   highest  wind   velocity,   (d)  the 
greatest  rainfall.     In  each  case  give  figures  and  name  of  place. 

3.  State  all  the  weather  conditions   shown  on  the  map  for 
your  own  city  or  the  nearest  Weather  Bureau  Station. 

4.  Compare  a  number  of  high  and  low  areas  on  different 
maps  and  explain  how  the  highs  differ  from  the  lows  as  regards 

(a)  pressure,  (b)  direction  of  winds,  (c)  temperature,  (d)  state  of 
weather  (rainy  or  clear). 

5.  Follow  the  course  of  a  low  area  on  several  consecutive 
maps  and  estimate  (a)  about  how  far  the  area  travels  in  a  day, 

(b)  and  in  what  direction. 

I  6.  Secure  the  latest  weather  map  and  prophesy  what  you 
think  the  weather  will  be  for  your  locality  for  the  next  day. 
When  the  time  comes,  make  a  note  of  the  actual  conditions  and 
see  how  near  you  came  to  them. 


SUPPLEMENTARY    QUESTIONS   FOR    CLASS    DISCUSSION 

1.  To  what  people  are  the  weather  forecasts  of  the  Weather 
Bureau  of  greatest  value? 

2.  What  does  a  weather  map  show? 

3.  How  is  a  weather  map  made? 


REFERENCE 

Harrington,  About  the  Weather,  D.  Appleton,  New  York  City. 


SECTION   G 
THE  HEAVENLY  BODIES 

CHAPTER   XXXII 

THE   EARTH   AS   A   PART   OF  THE   SOLAR   SYSTEM 

1.  In  what  ways  are  the  sun  and  moon  dif- 
ferent ? 

2.  How  do  stars  differ  from  planets? 

Solar  system.  The  earth  is  but  one  of  many  heavenly 
bodies  scattered  through  space.  In  this  chapter  we  will 
try  to  obtain  some  idea  of  these  bodies  and  of  their  relation 
to  the  earth.  The  earth,  the  other  planets,  the  moon,  and 
the  sun  are  included  together  in  what  is  called  the  solar 
system.  The  center  of  this  system  is  the  sun.  Revolving 
around  this  sun  are  the  planets  situated  at  varying  distances 
from  the  common  center.  Some  of  these,  such  as  Mercury 
and  Venus,  are  nearer  the  sun  than  is  the  earth ;  others, 
such  as  Mars,  Saturn,  Uranus,  and  Neptune,  are  farther 
away  than  the  earth. 

The  positions  of  these  planets  may  be  illustrated  by 
means  of  circles,  as  shown  in  figure  206.  The  dot  in  the 
center  represents  the  sun.  The  circles  represent  the  orbits 
of  the  various  planets.  If  one  inch  be  taken  to  represent 
the  distance  of  the  earth  from  the  sun,  then  to  represent  the 
orbit  of  the  moon,  a  circle  should  be  drawn  around  the  earth 
at  a  distance  of  one  four-hundredth  of  an  inch  from  it. 
This  is  too  small  to  be  shown  on  this  diagram.  All  these 

515 


SCIENCE  OF  HOME  AND   COMMUNITY 


bodies  of  the  solar  system,  the  planets,  moons,  and  sun  form 
a  single  group  and  are  relatively  very  close  together,  com- 
pared with  the  distance  from  the  stars.  If  we  were  to  make 
a  dot  to  represent  the  position  of  the  nearest  star  on  the 
same  scale,  it  would  be  almost  four  miles  away. 


Neptune 


FIG.  206.  —  Solar  system,  showing  the  relative  distances  from  sun,  the  relative 
size  of  the  orbits,  the  number  of  satellites,  and  the  period  of  revolution. 

Relative  distances  of  sun  and  stars.  Hold  the  hand  with 
the  fingers  spread  so  that  the  tip  of  the  third  finger  is  about 
six  inches  from  the  thumb.  Let  the  thumb  represent  the 
sun,  and  the  four  fingers  represent  the  position  of  the  first 
four  planets,  Mercury,  Venus,  Earth,  and  Mars.  Then, 
proportionately,  the  nearest  star  would  be  at  a  distance  of 
almost  twenty-five  miles,  and  the  North  Star  would  be  at  a 
distance  of  over  two  hundred  and  fifty  miles,  while  the  most 
distant  stars  would  be  at  a  distance  greater  than  the  entire 
width  of  the  United  States  from  New  York  to  San  Francisco. 
This  illustrates  the  fact  that  while  the  distances  between  the 


THE   EARTH  AS   A   PART   OF   THE   SOLAR   SYSTEM     517 

earth  and  sun  and  bodies  of  the  solar  system  seem  large 
as  compared  with  the  distances  on  the  earth,  yet  they  are 
very  small  when  compared  with  the  distances  between  the 
earth  and  the  stars. 

Motion  of  earth.  The  earth  is  traveling  around  the  sun 
at  a  tremendous  speed  in  its  annual  orbit.  During  the  yearly 
journey  we  are  traveling  through  space  at  the  rate  of  eighteen 
miles  every  second.  Every  twenty-five  minutes  we  travel 
a  distance  equal  to  the  circumference  of  the  earth,  every 
four  hours  a  distance  equal  to  that  to  the  moon,  and  every 
two  months  a  distance  equal  to  that  to  the  sun. 

At  the  same  time  we  are  moving  in  another  direction, 
through  the  daily  rotation  of  the  earth.  People  at  the 
equator  travel  at  the  rate  of  a  thousand  miles  an  hour.  We 
do  not  realize  that  we  are  moving  in  these  two  ways  because 
all  the  objects  on  the  earth  are  moving  with  us  and  we  are 
all  held  on  the  earth  by  the  action  of  gravity. 

Sun.  The  sun  is  the  center  of  the  solar  system,  around 
which  the  planets  revolve,  and  it  is  by  far  the  largest  body  in 
the  system.  Its  diameter  is  almost  nine  hundred  thousand 
miles,  about  one  hundred  times  that  of  the  earth.  If  the 
size  of  the  earth  were  represented  by  a  marble  a  half -inch 
in  diameter,  it  would  take  a  sphere  four  feet  through  to 
represent  the  sun.  Or  if  a  baseball  were  taken  to  represent 
the  earth,  it  would  take  a  sphere  about  twenty-five  feet  in 
diameter  to  represent  the  sun.  If  we  could  imagine  the 
earth  to  be  placed  at  the  center  of  the  sun  with  the  moon 
at  its  average  distance  away,  the  sun  would  extend  out  to 
the  moon  and  almost  as  far  beyond  it. 

The  distance  from  the  earth  to  the  sun  varies  from  month 
to  month.  Strange  as  it  may  seem,  we  are  nearer  the  sun 
in  winter  than  in  summer.  The  average  distance  is  ninety- 
three  million  miles. 

Sun's  heat.  The  sun  is  the  source  of  the  heat  and  light 
that  make  life  possible  on  the  earth.  Without  the  sun's 


SCIENCE   OF   HOME   AND    COMMUNITY 


heat  every  living  thing  on  the  earth  would  perish.  We 
naturally  wonder  how  the  sun  is  able  to  give  out  so  much 
heat  for  such  long  periods  of  time.  We  know  that  it  is  not 
by  the  ordinary  process  of  burning  with  which  we  are  famil- 
iar;, because  if  it  were  so,  the  sun  would  have  burned  up 
before  this.  Astronomers  tell  us  that  the  heat  is  given  out 
by  the  contraction  of  the  sun,  and  that  the  sun  is  all  the  time 
becoming  smaller.  The  change  is  so  slight,  however,  that 
even  with  the  most  powerful  telescope,  man  cannot  notice 
any  difference  in  the  size  of  the  sun. 


FIG    207.  —  Spectroscope,  an  instrument  by  means  of  which  many  things  have 
been  learned  about  the  sun  and  stars. 

Composition  of  the  sun.  One  very  remarkable  thing  that 
man  has  been  able  to  do  is  to  find  out  some  things  of  which 
the  sun  is  made,  although  it  is  situated  at  such  a  great 
distance.  This  has  been  done  by  means  of  the  spectroscope. 
This  is  an  instrument  for  making  and  viewing  a  spectrum. 
When  sunlight  passes  through  a  glass  prism  of  a  certain 
shape,  the  ordinary  white  light  is  broken  up  into  a  number 
of  colored  lights,  as  in  the  rainbow.  When  this  spectrum 
is  looked  at  with  a  telescope,  it  is  found  to  contain  a  great 
many  dark  lines  crossing  it.  From  the  number  and  position 
of  these  lines  it  is  possible  to  tell  what  substances  must  be 


THE  EARTH  AS  A  PART  OF  THE  SOLAR  SYSTEM    519 

in  the  sun  in  order  to  make  these  lines,  because  these  lines 
are  the  same  as  those  made  by  certain  substances  found  on 
the  earth.  Such  metals  as  iron  and  nickel  have  been  found 
to  be  present  in  the  sun.  It  is  to  be  expected  that  the 
same  elements  would  be  found  in  both  the  earth  and  sun, 
because  it  is  believed  that  they  came  originally  from  the  same 
mass.  The  outer  surface  of  the  sun  is  made  up  of  hot  gases, 
heated  to  an  extremely  high  temperature.  What  are  called 
sunspots  are  frequently  seen  on  the  surface  of  the  sun. 
These  are  believed  to  be  enormous  depressions  or  craters  in 
these  gases.  Farther  in  from  the  surface,  these  gases  be- 
come very  dense  and  in  the  center  may  become  liquid  or 
even  solid. 

The  sun  is  found  to  rotate  on  its  axis  like  the  earth,  only  its 
period  of  rotation  is  longer.  Observation  of  sunspots  shows 
that  it  takes  the  sun  about  twenty-five  days  to  rotate  once. 

Changes  in  the  solar  system.  All  the  bodies  of  the  solar 
system  are  going  through  a  series  of  changes.  At  one  time 
all  were  intensely  hot.  The  sun  is  in  that  stage  now,  and 
possibly  Jupiter  is.  The  earth  represents  a  later  stage, 
when  the  crust  is  cool  but  the  interior  is  hot  as  shown  by 
volcanoes.  The  moon  represents  a  still  later  stage,  for  it 
has  lost  nearly  all  its  heat  and  is  probably  cooled  all  the  way 
through.  In  time  the  sun  too  will  doubtless  become  cool 
and  cease  to  give  off  heat  and  light,  but  that  is  many  million 
years  in  the  future. 

The  seasons.  Our  change  of  seasons  is  due  to  the  varying 
amounts  of  heat  we  receive  from  the  sun.  In  the  summer 
the  north  pole  of  the  earth  points  towards  the  sun  and  during 
the  middle  of  the  day  the  rays  come  down  nearly  straight. 
In  the  winter  the  north  pole  of  the  earth  points  away  from 
the  sun,  which  is  low  down  in  the  sky  at  noon,  and  the 
rays  strike  the  earth  obliquely,  so  that  less  rays  strike  a 
given  surface  than  in  the  summer  when  the  rays  are  more 
nearly  vertical.  Hence  the  earth  receives  more  heat  during 


520  SCIENCE  OF  HOME  AND   COMMUNITY 

the  summer  than  winter.  This  inclination  of  the  sun's 
rays  has  more  effect  in  producing  the  change  of  seasons 
than  our  distance  from  the  sun.  This  explains  the  fact  that 
we  have  our  winter  when  we  do,  in  spite  of  the  fact  that  we 
are  nearer  the  sun  at  that  time.  The  fact  that  the  sun 
shines  for  a  longer  part  of  the  day  in  summer  than  in  winter 
is  another  reason  why  our  summers  are  hotter.  In  the 
southern  hemisphere  the  conditions  and  the  seasons  are 
the  reverse  of  those  in  the  northern  hemisphere. 

Moon.  As  the  earth  revolves  around  the  sun,  so  the  moon 
revolves  around  the  earth.  While  the  earth